drm/i915: select framebuffer support automatically

Migration helper.

The i915 driver recently added a 'depends on FB' rule to its
Kconfig entry - which silently turns off DRM_I915 if someone
has a working config but no CONFIG_FB selected, and upgrades
to the latest upstream kernel.

Norbert Preining reported this problem:

   Bug-Entry   : http://bugzilla.kernel.org/show_bug.cgi?id=12599
   Subject     : dri /dev node disappeared with 2.6.29-rc1

So change it to "select FB", which auto-selects framebuffer
support. This way the driver keeps working, regardless of
whether FB was enabled before or not.

Kconfig select's of interactive options can be problematic to
dependencies and can cause build breakages - but in this case
it's safe because it's a leaf entry with no dependencies of its
own.

( There is some minor circular dependency fallout as FB_I810
  and FB_INTEL also used 'depends on FB' constructs - update
  those to "select FB" too. )
Reported-by: Norbert Preining <preining@logic.at>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Dave Airlie <airlied@linux.ie>

drivers/gpu/drm/Kconfig

@@ -70,7 +70,7 @@ config DRM_I915
 	select FB_CFB_FILLRECT
 	select FB_CFB_COPYAREA
 	select FB_CFB_IMAGEBLIT
-	depends on FB
+	select FB
 	tristate "i915 driver"
 	help
 	  Choose this option if you have a system that has Intel 830M, 845G,

drivers/video/Kconfig

@@ -1054,9 +1054,10 @@ config FB_RIVA_BACKLIGHT
 
 config FB_I810
 	tristate "Intel 810/815 support (EXPERIMENTAL)"
-	depends on FB && EXPERIMENTAL && PCI && X86_32
+	depends on EXPERIMENTAL && PCI && X86_32
 	select AGP
 	select AGP_INTEL
+	select FB
 	select FB_MODE_HELPERS
 	select FB_CFB_FILLRECT
 	select FB_CFB_COPYAREA
@@ -1119,7 +1120,8 @@ config FB_CARILLO_RANCH
 
 config FB_INTEL
 	tristate "Intel 830M/845G/852GM/855GM/865G/915G/945G/945GM/965G/965GM support (EXPERIMENTAL)"
-	depends on FB && EXPERIMENTAL && PCI && X86
+	depends on EXPERIMENTAL && PCI && X86
+	select FB
 	select AGP
 	select AGP_INTEL
 	select FB_MODE_HELPERS