[PORT FROM R2] FB: reduce the prepare time for display logo

[PORT FROM R2] FB: reduce the prepare time for display logo

BZ: 16563

Borqs-Id: 9400eaacfe2e96ed81af199ed51b2fd475a273ea
Borqs-Contact: b094 <leo.he@borqs.com>
Commit-Date: Mon Sep 19 01:30:04 PDT 2011

borqsbtx: 5085

Reduce the prepare time for display logo:
1) enable VT_BUF_VRAM_ONLY for MFLD platform
2) remove the buffer reset in psb_fb.c

These two changes will help to remove the LOGO flicker between IAFW and Linux.

Orig-Change-Id: I43dc5ec33bd76b0c41f943510c339f70183be905
Signed-off-by: Leo He <leo.he@borqs.com>
Conflicts:

	drivers/char/vt.c

Change-Id: Ieacde3f704dc07a3a27aa850a754948a91e0a64f
Reviewed-on: http://android.intel.com:8080/33087
Reviewed-by: Chotard, Celine <celine.chotard@intel.com>
Tested-by: Chotard, Celine <celine.chotard@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>