memset uses rep stosb on x86 during boot, with memory
not set to write-combining, which makes it slow.
Instead we do aligned writes of 2 x four bytes at once.
Only clear the minimum of size and width * height * 4
UEFI framebuffer size can be huge, upto 512MB here,
and rep stosb seems to be around 25-30MB/s
This is written as generic as possible to work on
old compilers and different platforms, without
expecting boot memset to be optimized.
This makes it almost unnoticable compared to not
clearing.
Writes to videomem is slow without memory remapping
Can't do the mapping without leaving UEFI, so skipping
the clear. Afaict it should always be cleared by UEFI
This saves ~10 seconds of booting on my machine
(1920*1080*4 bytes)
EFI video mode (should have been it's own commit)
* Only do strcmp if there are enough params
* break when found
