Switch ramdisk.img to the LZ4 format

Bug: 169336853
Test: file out/target/product/emulator_x86_64/ramdisk.img
Signed-off-by: Roman Kiryanov <rkir@google.com>
Change-Id: I085d230a49cd92cc7fe3a620eec411d0e8b90667
diff --git a/target/board/BoardConfigEmuCommon.mk b/target/board/BoardConfigEmuCommon.mk
index 07b07ce..6b2291f 100644
--- a/target/board/BoardConfigEmuCommon.mk
+++ b/target/board/BoardConfigEmuCommon.mk
@@ -77,6 +77,7 @@
 BOARD_BOOT_HEADER_VERSION := 3
 BOARD_MKBOOTIMG_ARGS += --header_version $(BOARD_BOOT_HEADER_VERSION)
 BOARD_VENDOR_BOOTIMAGE_PARTITION_SIZE := 0x06000000
+BOARD_RAMDISK_USE_LZ4 := true
 
 # Enable chain partition for system.
 BOARD_AVB_SYSTEM_KEY_PATH := external/avb/test/data/testkey_rsa2048.pem