video: Kconfig: Make VESA driver avaiable for non-x86 boards

There is no reason to prevent CONFIG_VIDEO_VESA driver working on
non-x86 boards, so remove such limitation.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>

drivers/video/Kconfig

 config VIDEO_VESA
 	bool "Enable VESA video driver support"
-	depends on X86
 	default n
 	help
 	  Turn on this option to enable a very simple driver which uses vesa