Merge changes I7bd61f74,Ia84e604a,I75e13b92,I0db2af20,I4feac435

* changes:
  Mount generic ramdisk as readwrite.
  Do not put GENERIC_KERNEL_CMDLINE in recovery image.
  Move common code out of the conditional.
  Remove device-specific bits if recovery_as_boot
  Do not assume GKI just with vendor_boot.