treewide [Kconfig]: Remove useless comment

Change-Id: I3dafffa61f4fe6089fd11ef6579626aff8088df5
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50185
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

payloads/external/U-Boot/Kconfig

@@ -1,6 +1,6 @@
 if PAYLOAD_UBOOT
 
-config PAYLOAD_SPECIFIC_OPTIONS # dummy
+config PAYLOAD_SPECIFIC_OPTIONS
 	def_bool y
 	select PAYLOAD_IS_FLAT_BINARY