yocto-bsp: drop 4.15 bbappend

4.18 is replacing 4.15 as the latest kernel in the upcoming
release, so we drop this dangling bbappend.

(From meta-yocto rev: 14e89c34cc0cb9e74075cd5a86500426701b1c8d)

Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta-yocto-bsp/recipes-kernel/linux/linux-yocto_4.15.bbappend

@@ -1,27 +0,0 @@
-KBRANCH_genericx86  = "v4.15/standard/base"
-KBRANCH_genericx86-64  = "v4.15/standard/base"
-KBRANCH_edgerouter = "v4.15/standard/edgerouter"
-KBRANCH_beaglebone-yocto = "v4.15/standard/beaglebone"
-KBRANCH_mpc8315e-rdb = "v4.15/standard/fsl-mpc8315e-rdb"
-
-KMACHINE_genericx86 ?= "common-pc"
-KMACHINE_genericx86-64 ?= "common-pc-64"
-KMACHINE_beaglebone-yocto ?= "beaglebone"
-
-SRCREV_machine_genericx86    ?= "51273ff79f4ad930f4a788257f58e1266cb236e3"
-SRCREV_machine_genericx86-64 ?= "51273ff79f4ad930f4a788257f58e1266cb236e3"
-SRCREV_machine_edgerouter ?= "3373c0cf71f2812eeb9694839456df6f67fd32ac"
-SRCREV_machine_beaglebone-yocto ?= "e25dbfe95302eeaa1a03a828d05c09479574488a"
-SRCREV_machine_mpc8315e-rdb ?= "0b32edc46dfe7c40bf5451e9b7533c823bb2c6c4"
-
-COMPATIBLE_MACHINE_genericx86 = "genericx86"
-COMPATIBLE_MACHINE_genericx86-64 = "genericx86-64"
-COMPATIBLE_MACHINE_edgerouter = "edgerouter"
-COMPATIBLE_MACHINE_beaglebone-yocto = "beaglebone-yocto"
-COMPATIBLE_MACHINE_mpc8315e-rdb = "mpc8315e-rdb"
-
-LINUX_VERSION_genericx86 = "4.15.18"
-LINUX_VERSION_genericx86-64 = "4.15.18"
-LINUX_VERSION_edgerouter = "4.15.18"
-LINUX_VERSION_beaglebone-yocto = "4.15.18"
-LINUX_VERSION_mpc8315e-rdb = "4.15.18"