rockchip: common: enter fastboot when avb+ab system boot failed

When avb+ab system boot failed, it means slot a/b is unbootable
and slot_cnt_a/b is zero. We should update images a/b and
active slot again, and this can be done by fastboot. Remove
rockusb from RKIMG_BOOTCOMMAND since rockusb unable to active slot.

Change-Id: Ib9b15940a5b8f0cefe9a91ee7564ea8f9aa6f201
Signed-off-by: Zain Wang <wzz@rock-chips.com>

include/configs/rockchip-common.h

@@ -126,12 +126,24 @@
 	"fi; \0"
 
 #ifdef CONFIG_AVB_VBMETA_PUBLIC_KEY_VALIDATE
+#ifndef CONFIG_ANDROID_AB
 #define RKIMG_BOOTCOMMAND \
 	"boot_android ${devtype} ${devnum};" \
 	"echo AVB boot failed and enter rockusb or fastboot!;" \
 	"rockusb 0 ${devtype} ${devnum};" \
 	"fastboot usb 0;"
 #else
+/*
+ * Update images a/b and active slot with fastboot
+ * when avb+ab system boot failed.
+ * Remove rockusb since it unable to active slot.
+ */
+#define RKIMG_BOOTCOMMAND \
+	"boot_android ${devtype} ${devnum};" \
+	"echo AVB boot failed and enter fastboot!;" \
+	"fastboot usb 0;"
+#endif /* CONFIG_ANDROID_AB */
+#else /* CONFIG_AVB_VBMETA_PUBLIC_KEY_VALIDATE */
 #define RKIMG_BOOTCOMMAND \
 	"boot_android ${devtype} ${devnum};" \
 	"bootrkp;" \