Kconfig: Introduce HAVE_(VBE_)LINEAR_FRAMEBUFFER

Like HAVE_VGA_TEXT_FRAMEBUFFER, these are selected by graphics drivers
that support a linear framebuffer. Some related settings moved to the
drivers (i.e. for rockchip/rk3288 and nvidia/tegra124) since they are
hardcoded.

Change-Id: Iff6dac5a5f61af49456bc6312e7a376def02ab00
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/19800
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/northbridge/intel/x4x/Kconfig

@@ -25,6 +25,7 @@ config NORTHBRIDGE_SPECIFIC_OPTIONS # dummy
 	select VGA
 	select INTEL_GMA_ACPI
 	select RELOCATABLE_RAMSTAGE
+	select HAVE_LINEAR_FRAMEBUFFER if MAINBOARD_DO_NATIVE_VGA_INIT
 	select HAVE_VGA_TEXT_FRAMEBUFFER if MAINBOARD_DO_NATIVE_VGA_INIT
 
 config CBFS_SIZE