Add drm drivers for hardware with no currently loaded drm driver

Add drivers for all PCI display class devices, even if they do not have
a drm driver loaded at the time of mkinitrd being run.

The DRM_WHITELIST patch should be used with this one, in order to avoid
putting non-KMS drivers into initrd.

# Please enter the commit message for your changes. Lines starting
# with '#' will be ignored, and an empty message aborts the commit.
#
# Committer: Anssi Hannula <anssi@mandriva.org>
#
# On branch mandriva
# Your branch is ahead of 'origin/mandriva' by 2 commits.
#
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#	modified:   mkinitrd
#
# Untracked files:
#   (use "git add <file>..." to include in what will be committed)
#
#	mkinitrd-RNE
#	mkinitrd~