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>
diff --git a/src/northbridge/intel/i945/Kconfig b/src/northbridge/intel/i945/Kconfig
index 8492d77..482f98a 100644
--- a/src/northbridge/intel/i945/Kconfig
+++ b/src/northbridge/intel/i945/Kconfig
@@ -43,6 +43,15 @@
 	default "8086,27a2" if NORTHBRIDGE_INTEL_SUBTYPE_I945GM
 	default "8086,2772" if NORTHBRIDGE_INTEL_SUBTYPE_I945GC
 
+config I945_LVDS
+	def_bool n
+	select MAINBOARD_HAS_NATIVE_VGA_INIT
+	select HAVE_LINEAR_FRAMEBUFFER if MAINBOARD_DO_NATIVE_VGA_INIT
+	help
+	  Selected by mainboards that use native graphics initialization
+	  for the LVDS port. A linear framebuffer is only supported for
+	  LVDS.
+
 config CHANNEL_XOR_RANDOMIZATION
 	bool
 	default n