arm: rockchip_linux_config: enable scsi scan async

Enable CONFIG_SCSI_SCAN_ASYNC to probe device on
different buses in parallel, it can speed up the
USB 3.0 UAS disk enumeration on rockchip platform.

Change-Id: I0db76b9326b9ea2700f925ed9d79c2c9470228e7
Signed-off-by: William Wu <william.wu@rock-chips.com>

Author: wuliangfeng

arch/arm/configs/rockchip_linux_defconfig

@@ -168,6 +168,7 @@ CONFIG_BLK_DEV_RAM_COUNT=1
 CONFIG_SCSI=y
 CONFIG_BLK_DEV_SD=y
 CONFIG_BLK_DEV_SR=y
+CONFIG_SCSI_SCAN_ASYNC=y
 CONFIG_SCSI_SPI_ATTRS=y
 CONFIG_MD=y
 CONFIG_BLK_DEV_DM=y