[coreboot] rfc - gcc builtins and memset memcpy memmove memcmp

[Marc Jones]

Now that we have addressed the CAR/MMIO ROM copy issue (thanks Scott
and Arne), I wanted to revisit the other change that Arne proposed for
memset.

http://article.gmane.org/gmane.linux.bios/57707

Some people didn't like the architecture specific code for memset. I
don't have a problem with it, but it did bring up a few questions.

1. Why isn't gcc generating the rep stosb itself? This should be a
standard optimization.

2. Why do we have functions for memset, memcpy, etc, when gcc has
builtins that could be used? Is this a remnant from romcc?

Marc