rpi-base: Add missing overlay_map.dtb and vc4-kms-v3d-pi4.dtbo

overlay_map.dtb arranges that when config.txt requests "vc4-kms-v3d"
the rpi4 will actually load "vc4-kms-v3d-pi4" and fixups like that.
It is present on the official distros, and must be put into the
overlays subdirectory in the boot partition.
For a detailed description of the overlay_map.dts file see:
  https://www.raspberrypi.org/documentation/configuration/device-tree.md#part2.2.10

vc4-kms-v3d-pi4 is required for the arm based kms driver on the rpi4.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>

conf/machine/include/rpi-base.inc

@@ -15,6 +15,7 @@ XSERVER = " \
     "
 
 RPI_KERNEL_DEVICETREE_OVERLAYS ?= " \
+    overlays/overlay_map.dtb \
     overlays/at86rf233.dtbo \
     overlays/disable-bt.dtbo \
     overlays/dwc2.dtbo \
@@ -44,6 +45,7 @@ RPI_KERNEL_DEVICETREE_OVERLAYS ?= " \
     overlays/rpi-poe.dtbo \
     overlays/vc4-fkms-v3d.dtbo \
     overlays/vc4-kms-v3d.dtbo \
+    overlays/vc4-kms-v3d-pi4.dtbo \
     overlays/vc4-kms-dsi-7inch.dtbo \
     overlays/w1-gpio.dtbo \
     overlays/w1-gpio-pullup.dtbo \
@@ -110,17 +112,17 @@ def make_dtb_boot_files(d):
 
     def transform(dtb):
         base = os.path.basename(dtb)
-        if dtb.endswith('dtb'):
-            # eg: whatever/bcm2708-rpi-b.dtb has:
-            #     DEPLOYDIR file: bcm2708-rpi-b.dtb
-            #     destination: bcm2708-rpi-b.dtb
-            return base
-        elif dtb.endswith('dtbo'):
+        if dtb.endswith('dtbo') or base == 'overlay_map.dtb':
             # overlay dtb:
             # eg: overlays/hifiberry-amp.dtbo has:
             #     DEPLOYDIR file: hifiberry-amp.dtbo
             #     destination: overlays/hifiberry-amp.dtbo
             return '{};{}'.format(base, dtb)
+        elif dtb.endswith('dtb'):
+            # eg: whatever/bcm2708-rpi-b.dtb has:
+            #     DEPLOYDIR file: bcm2708-rpi-b.dtb
+            #     destination: bcm2708-rpi-b.dtb
+            return base
 
     return ' '.join([transform(dtb) for dtb in alldtbs.split(' ') if dtb])