sdm845: commonize device

The only difference between beryllium, enchilada and sdm845 is
naming of various modules and fstabs.

Allow to override the fstab target of sdm845 and switch to use
`TARGET_BOOTLOADER_BOARD_NAME` for naming files.

This slims down the differences of beryllium, enchilada and
sdm845 device makefiles to a minimum.

Change-Id: Icfa0b0c1b1729e4e071b33c31d522f14679cdc0e
Signed-off-by: Alexander Martinz <amartinz@shiftphones.com>
diff --git a/sdm845/device.mk b/sdm845/device.mk
index 3349e9d..4c320b3 100644
--- a/sdm845/device.mk
+++ b/sdm845/device.mk
@@ -21,10 +21,12 @@
 # setup dalvik vm configs
 $(call inherit-product, frameworks/native/build/phone-xhdpi-2048-dalvik-heap.mk)
 
+# Allow to override ramdisk until we can produce fully generic builds
+RAMDISK_FSTAB_TARGET ?= $(LOCAL_PATH)/fstab.ramdisk
 
 PRODUCT_COPY_FILES := \
-    $(LOCAL_PATH)/fstab.ramdisk:$(TARGET_COPY_OUT_RAMDISK)/fstab.sdm845 \
-    $(LOCAL_PATH)/fstab.ramdisk:$(TARGET_COPY_OUT_VENDOR)/etc/fstab.sdm845 \
+    $(RAMDISK_FSTAB_TARGET):$(TARGET_COPY_OUT_RAMDISK)/fstab.sdm845 \
+    $(RAMDISK_FSTAB_TARGET):$(TARGET_COPY_OUT_VENDOR)/etc/fstab.sdm845 \
     device/generic/sdm845/init.common.rc:$(TARGET_COPY_OUT_VENDOR)/etc/init/init.sdm845.rc \
     device/generic/sdm845/init.common.usb.rc:$(TARGET_COPY_OUT_VENDOR)/etc/init/init.sdm845.usb.rc \
     device/generic/sdm845/common.kl:$(TARGET_COPY_OUT_VENDOR)/usr/keylayout/sdm845.kl