arm-bsp/linux-stable: move corstone700 tweaks to versioned bbappend

The corstone700-specific tweaks should be applied to just the 5.6
version of the linux-stable recipe, not all of them.  By appending all
of the versions they *all* become 5.6.14, which makes it impossible to
know what recipe is actually being used.

Change-Id: I77ccc1f16003fea7b6356732587c6947b20a2f4c
Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Jon Mason <jon.mason@arm.com>

meta-arm-bsp/recipes-kernel/linux/linux-stable_%.bbappend

@@ -1,11 +1,3 @@
 # Add support for Arm Platforms (boards or simulators)
 
 require linux-arm-platforms.inc
-
-#
-# Corstone700 KMACHINE
-#
-MACHINE_KERNEL_REQUIRE ?= ""
-MACHINE_KERNEL_REQUIRE_corstone700 = "linux-stable-corstone700.inc"
-
-require ${MACHINE_KERNEL_REQUIRE}

meta-arm-bsp/recipes-kernel/linux/linux-stable_5.6%.bbappend

@@ -0,0 +1,7 @@
+#
+# Corstone700 KMACHINE
+#
+MACHINE_KERNEL_REQUIRE ?= ""
+MACHINE_KERNEL_REQUIRE_corstone700 = "linux-stable-corstone700.inc"
+
+require ${MACHINE_KERNEL_REQUIRE}