Deprecate distinct boot paths for androidboot.emmc

Qualcomm used to require a "on emmc-fs" to distinguish multi-boot
devices, in replacement of the usual "on fs". This distinction has
been deprecated in jb, and it's breaking mako

Conflicts:

	init/Android.mk
	init/init.c

Change-Id: I8ef5c932efcd5e7f8d6f6fce0915683d84c3ee11