x86, AMD: Correct align_va_addr documentation

Commit dfb09f9b7ab0 ("x86, amd: Avoid cache aliasing penalties
on AMD family 15h") introduced a kernel command line parameter
called 'align_va_addr' which still refers to arguments used in
an earlier version of the patch and which got changed without
updating the documentation. Correct that omission.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Cc: Frank Arnold <frank.arnold@amd.com>
Link: http://lkml.kernel.org/r/1321873819-29541-1-git-send-email-bp@amd64.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>