airoha: Get rid of bootloader-emmc print during sysupgrade

During image verification before sysupgrade, the line "bootloader-emmc"
was printed to the output of platform_check_image. Silence the output of
the offending command.

Signed-off-by: Andreas Gnau <andreas.gnau@iopsys.eu>

airoha/base-files/lib/upgrade/platform.sh

@@ -16,7 +16,7 @@ __check_image_emmc_gpt_support() {
 	local image=$1
 	local board_name=$2
 	local configuration="$(get_configuration "$image" "$board_name")" || return 1
-	if [ "$(get_root_device_type)" = emmc ] && ! get_image_component_ref "$image" bootloader-emmc "$configuration" ; then
+	if [ "$(get_root_device_type)" = emmc ] && ! get_image_component_ref "$image" bootloader-emmc "$configuration" > /dev/null ; then
 		log "ERROR: Can not downgrade to image with missing eMMC GPT support."
 		return 1
 	fi