sdimage-raspberrypi.wks: increase /boot partition minimal size from 20 to 100

* current aarch64 kernel image alone is 24MB:
  24M tmp-glibc/deploy/images/raspberrypi4-64/Image-raspberrypi4-64-1-6.1.77+git0+43d1723dbe_77fc1fbcb5-r0.1-20110405230000.bin
  and with rpi-bootfiles it takes around 46MB (e.g. this is from kirkstone raspberrypi4-64 build):

2.0K    boot.scr
2.0K    cmdline.txt
4.0K    fixup4cd.dat
4.0K    fixup_cd.dat
4.0K    uEnv.txt
6.0K    fixup4.dat
8.0K    fixup.dat
10K     fixup4db.dat
10K     fixup4x.dat
10K     fixup_db.dat
10K     fixup_x.dat
16K     uboot.env
36K     config.txt
52K     bcm2711-rpi-4-b.dtb
52K     bcm2711-rpi-400.dtb
52K     bcm2711-rpi-cm4.dtb
52K     bootcode.bin
126K    overlays
558K    kernel8.img
786K    start4cd.elf
786K    start_cd.elf
2.2M    start4.elf
2.9M    start.elf
2.9M    start4x.elf
3.6M    start4db.elf
3.6M    start_x.elf
4.6M    start_db.elf
23M     Image

* it is increased automatically to fit the content:

  tmp-glibc/deploy/images/raspberrypi4-64 $ sfdisk -l core-image-minimal-raspberrypi4-64.rootfs--1.0-r0-20110405230000.wic
  Disk core-image-minimal-raspberrypi4-64.rootfs--1.0-r0-20110405230000.wic: 241.2 MiB, 252915712 bytes, 493976 sectors
  Units: sectors of 1 * 512 = 512 bytes
  Sector size (logical/physical): 512 bytes / 512 bytes
  I/O size (minimum/optimal): 512 bytes / 512 bytes
  Disklabel type: dos
  Disk identifier: 0x076c4a2a

  Device                                                                Boot  Start    End Sectors   Size Id Type
  core-image-minimal-raspberrypi4-64.rootfs--1.0-r0-20110405230000.wic1 *      8192 157815  149624  73.1M  c W95 FAT32 (LBA)
  core-image-minimal-raspberrypi4-64.rootfs--1.0-r0-20110405230000.wic2      163840 493975  330136 161.2M 83 Linux

  but if you want to update the kernel in place or add some additional files
  later, it might not be big enough, increase the minimal size from 20M to 100M

* reminder (as I forgot about it before):
  "--size" is just minimum

  https://docs.yoctoproject.org/ref-manual/kickstart.html
  says:

  --size: The minimum partition size. Specify as an integer value optionally followed by one of the units “k” / “K” for kibibyte, “M” for mebibyte and “G” for gibibyte. The default unit if none is given is “M”. You do not need this option if you use --source.
  --fixed-size: The exact partition size. Specify as an integer value optionally followed by one of the units “k” / “K” for kibibyte, “M” for mebibyte and “G” for gibibyte. The default unit if none is given is “M”. Cannot be specify together with --size. An error occurs when assembling the disk image if the partition data is larger than --fixed-size.

Signed-off-by: Martin Jansa <martin.jansa@gmail.com>

wic/sdimage-raspberrypi.wks

@@ -2,5 +2,5 @@
 # long-description: Creates a partitioned SD card image for use with
 # Raspberry Pi. Boot files are located in the first vfat partition.
 
-part /boot --source bootimg-partition --ondisk mmcblk0 --fstype=vfat --label boot --active --align 4096 --size 20
+part /boot --source bootimg-partition --ondisk mmcblk0 --fstype=vfat --label boot --active --align 4096 --size 100
 part / --source rootfs --ondisk mmcblk0 --fstype=ext4 --label root --align 4096