x86: dts: Remove coreboot_fb.dtsi

There is no need to keep a separate coreboot_fb.dtsi since now we
have a generic coreboot payload dts.

While we are here, this also remove the out-of-date description in
the documentation regarding to coreboot framebuffer driver with
U-Boot loaded as a payload from coreboot. As the testing result with
QEMU 2.5.0 shows, the driver just works like a charm.

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

arch/x86/dts/bayleybay.dts

@@ -15,7 +15,6 @@
 /include/ "reset.dtsi"
 /include/ "rtc.dtsi"
 /include/ "tsc_timer.dtsi"
-/include/ "coreboot_fb.dtsi"
 
 / {
 	model = "Intel Bayley Bay";

arch/x86/dts/chromebook_link.dts

@@ -8,7 +8,6 @@
 /include/ "reset.dtsi"
 /include/ "rtc.dtsi"
 /include/ "tsc_timer.dtsi"
-/include/ "coreboot_fb.dtsi"
 
 / {
 	model = "Google Link";

arch/x86/dts/chromebook_samus.dts

@@ -8,7 +8,6 @@
 /include/ "reset.dtsi"
 /include/ "rtc.dtsi"
 /include/ "tsc_timer.dtsi"
-/include/ "coreboot_fb.dtsi"
 
 / {
 	model = "Google Samus";

arch/x86/dts/chromebox_panther.dts

@@ -5,7 +5,6 @@
 /include/ "reset.dtsi"
 /include/ "rtc.dtsi"
 /include/ "tsc_timer.dtsi"
-/include/ "coreboot_fb.dtsi"
 
 / {
 	model = "Google Panther";

arch/x86/dts/coreboot_fb.dtsi

@@ -1,5 +0,0 @@
-/ {
-	coreboot-fb {
-		compatible = "coreboot-fb";
-	};
-};

arch/x86/dts/minnowmax.dts

@@ -14,7 +14,6 @@
 /include/ "reset.dtsi"
 /include/ "rtc.dtsi"
 /include/ "tsc_timer.dtsi"
-/include/ "coreboot_fb.dtsi"
 
 / {
 	model = "Intel Minnowboard Max";

doc/README.x86

@@ -412,17 +412,10 @@ To enable video you must enable these options in coreboot:
    - Set framebuffer graphics resolution (1280x1024 32k-color (1:5:5))
    - Keep VESA framebuffer
 
-And include coreboot_fb.dtsi in your board's device tree source file, like:
-
-   /include/ "coreboot_fb.dtsi"
-
 At present it seems that for Minnowboard Max, coreboot does not pass through
 the video information correctly (it always says the resolution is 0x0). This
 works correctly for link though.
 
-Note: coreboot framebuffer driver does not work on QEMU. The reason is unknown
-at this point. Patches are welcome if you figure out anything wrong.
-
 Test with QEMU for bare mode
 ----------------------------
 QEMU is a fancy emulator that can enable us to test U-Boot without access to