[coreboot-gerrit] Patch merged into coreboot/master: cbgfx: Use memset() for faster screen clearing if possible

the following patch was just integrated into master:
commit e9808b145f592db1cf9daaaad6ac42982f13f218
Author: Julius Werner 
Date:   Thu Jun 30 22:34:57 2016 -0700

cbgfx: Use memset() for faster screen clearing if possible

cbgfx currently makes a separate function call (recomputing some values)
    for every single pixel it draws. While we mostly don't care that much
    about display speed, this can become an issue if you're trying to paint
    the whole screen white on a lowly-clocked Cortex-A53. As a simple
    solution for these extreme cases, we can build a fast path into
    clear_screen() that just memset()s the whole framebuffer if the color
    and pixel format allow it.

BUG=chrome-os-partner:54416
    TEST=Screen drawing speed on Kevin visibly improves (from 2.5s to 3ms).

Change-Id: I22f032afbb86b96fa5a0cbbdce8526a905c67b58
    Signed-off-by: Julius Werner 
    Reviewed-on: https://review.coreboot.org/15524
    Tested-by: build bot (Jenkins)
    Reviewed-by: Daisuke Nojiri 
    Reviewed-by: Aaron Durbin

See https://review.coreboot.org/15524 for details.

-gerrit