cmd: mvebu: Hide bubt specific options when bubt is disabled

CONFIG_MVEBU_NAND_BOOT, CONFIG_MVEBU_SPI_BOOT, CONFIG_MVEBU_MMC_BOOT and
CONFIG_MVEBU_UBOOT_DFLT_NAME are unused when CONFIG_CMD_MVEBU_BUBT is not
enabled. So hide them.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/cmd/mvebu/Kconfig b/cmd/mvebu/Kconfig
index ac8b0af..39963db 100644
--- a/cmd/mvebu/Kconfig
+++ b/cmd/mvebu/Kconfig
@@ -9,6 +9,8 @@
 	  For details about bubt command please see the documentation
 	  in doc/mvebu/cmd/bubt.txt
 
+if CMD_MVEBU_BUBT
+
 choice
 	prompt "Flash for image"
 	default MVEBU_SPI_BOOT
@@ -49,6 +51,8 @@
 	  This option should contain a default file name to be used with
 	  MVEBU "bubt" command if the source file name is omitted
 
+endif
+
 config CMD_MVEBU_COMPHY_RX_TRAINING
 	bool "mvebu_comphy_rx_training"
 	depends on ARMADA_8K