arm: mediatek: build u-boot-mtk.bin only if needed

Not all MediaTek platforms needs u-boot-mtk.bin.

This patch will let u-boot generates u-boot-mtk.bin only if
CONFIG_MTK_BROM_HEADER_INFO is not empty.

diff --git a/Makefile b/Makefile
index 41adac7..93fa86a 100644
--- a/Makefile
+++ b/Makefile
@@ -1016,8 +1016,10 @@
 
 # Generate this input file for binman
 ifeq ($(CONFIG_SPL),)
+ifneq ($(patsubst "%",%,$(CONFIG_MTK_BROM_HEADER_INFO)),)
 INPUTS-$(CONFIG_ARCH_MEDIATEK) += u-boot-mtk.bin
 endif
+endif
 
 # Add optional build target if defined in board/cpu/soc headers
 ifneq ($(CONFIG_BUILD_TARGET),)
diff --git a/arch/arm/mach-mediatek/Kconfig b/arch/arm/mach-mediatek/Kconfig
index 39eea05..673ceb1 100644
--- a/arch/arm/mach-mediatek/Kconfig
+++ b/arch/arm/mach-mediatek/Kconfig
@@ -160,9 +160,8 @@
 
 config MTK_BROM_HEADER_INFO
 	string
-	default "media=nor" if TARGET_MT8518 || TARGET_MT8512 || TARGET_MT7629 || TARGET_MT7622
+	default "media=nor" if TARGET_MT8518 || TARGET_MT8512 || TARGET_MT7629
 	default "media=emmc" if TARGET_MT8516 || TARGET_MT8365 || TARGET_MT8183
-	default "media=snand;nandinfo=2k+64" if TARGET_MT7981 || TARGET_MT7986 || TARGET_MT7987 || TARGET_MT7988
 	default "lk=1" if TARGET_MT7623
 
 config MTK_TZ_MOVABLE