build: recovery: Support adding device-specific items

Change-Id: I25205e68282680932917016646dabd1abadbfce6
product_config: Set CM_BUILD priority above TARGET_BUILD_APPS

Even if we are doing TARGET_BUILD_APPS, we may want to use a cm
target for building.

Change-Id: Ic8053bc679fa8b726be90e611aeaacdf1850cabc

Conflicts:
	core/product_config.mk