mvebu: move subtarget image Makefile switch to parent Makefile

This moves the if conditions for choosing which image Makefiles
are used to the parent image/Makefile. It seems more convenient
to have "codeflow" in the parent while the subtarget-specific
files only contain the definitions.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Acked-by: Tomasz Maciej Nowak <tomek_n@o2.pl>

target/linux/mvebu/image/Makefile

@@ -116,8 +116,16 @@ define Device/NAND-512K
   PAGESIZE := 4096
 endef
 
+ifeq ($(SUBTARGET),cortexa9)
 include cortex-a9.mk
+endif
+
+ifeq ($(SUBTARGET),cortexa53)
 include cortex-a53.mk
+endif
+
+ifeq ($(SUBTARGET),cortexa72)
 include cortex-a72.mk
+endif
 
 $(eval $(call BuildImage))

target/linux/mvebu/image/cortex-a53.mk

-ifeq ($(SUBTARGET),cortexa53)
-
 define Device/globalscale_espressobin
   $(call Device/Default-arm64)
   DEVICE_VENDOR := Marvell
@@ -73,5 +71,3 @@ define Device/methode_udpu
   BOOT_SCRIPT := udpu
 endef
 TARGET_DEVICES += methode_udpu
-
-endif

target/linux/mvebu/image/cortex-a72.mk

-ifeq ($(SUBTARGET),cortexa72)
-
 define Device/marvell_macchiatobin
   $(call Device/Default-arm64)
   DEVICE_VENDOR := SolidRun
@@ -29,5 +27,3 @@ define Device/marvell_armada7040-db
   IMAGE/sdcard.img.gz := boot-img-ext4 | sdcard-img-ext4 | gzip | append-metadata
 endef
 TARGET_DEVICES += marvell_armada7040-db
-
-endif

target/linux/mvebu/image/cortex-a9.mk

@@ -6,8 +6,6 @@
 # See /LICENSE for more information.
 #
 
-ifeq ($(SUBTARGET),cortexa9)
-
 define Device/linksys
   $(Device/NAND-128K)
   DEVICE_VENDOR := Linksys
@@ -218,5 +216,3 @@ define Device/cznic_turris-omnia
   SUPPORTED_DEVICES += armada-385-turris-omnia
 endef
 TARGET_DEVICES += cznic_turris-omnia
-
-endif