[coreboot] Some typos in raminit_f.c (Re: r3866 - trunk/coreboot-v2/src/northbridge/amd/amdk8)

[Paul Menzel]

Dear list,

this patch fixes two(?) typos, capitalizes dimm in some comments and
adds some full stops in some comments.

Thanks,

Paul

Signed-off-by: Paul Menzel