drm/nouveau: Fix build regression, undefined reference to `acpi_video_get_edid'

Build breakage:

drivers/built-in.o: In function `nouveau_acpi_edid':
(.text+0x13404e): undefined reference to `acpi_video_get_edid'
make: *** [.tmp_vmlinux1] Error 1

Introduced by:

a6ed76d7 is the first bad commit
commit a6ed76d7
Author: Ben Skeggs <bskeggs@redhat.com>
Date:   Mon Jul 12 15:33:07 2010 +1000

    drm/nouveau: support fetching LVDS EDID from ACPI

    Based on a patch from Matthew Garrett.

    Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
    Acked-by: Matthew Garrett <mjg@redhat.com>

It doesn't seem to revert cleanly, but the problem lies in these
two config entries:

CONFIG_ACPI=y
CONFIG_ACPI_VIDEO=m

Adding a select for ACPI_VIDEO appears to be the best solution, and
is comparable to what is done in DRM_I915.  Builds, boots, and appears to
work correctly.

Signed-off-by: Philip J. Turmel <philip@turmel.org>
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>