Revert "Mount generic ramdisk as readwrite."

This reverts commit 78b55b224408dc956f64f826fc666bc8df70e61d.

Reason for revert: Replaced by Ib99aca13d4d:
ANDROID: GKI: build in a kernel command line of "rw"

Prebuilt is checked in at Ie34b5b017:
Update kernel to builds 6964541

Fixes: 171512004
Test: TH

Change-Id: I2aec88cc22483a6b3a671fc664d465624a14e5b0
diff --git a/core/Makefile b/core/Makefile
index add62b4..91b9616 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -711,10 +711,6 @@
   BUILT_BOOTIMAGE_TARGET := $(PRODUCT_OUT)/boot.img
 endif
 
-# kernel cmdline for GKI
-GENERIC_KERNEL_CMDLINE := rw
-.KATI_READONLY := GENERIC_KERNEL_CMDLINE
-
 INTERNAL_PREBUILT_BOOTIMAGE :=
 
 my_installed_prebuilt_gki_apex := $(strip $(foreach package,$(PRODUCT_PACKAGES),$(if $(ALL_MODULES.$(package).EXTRACTED_BOOT_IMAGE),$(package))))