Prefix the warn and error macros with the respective string so that
callers don't have to say "Error" or "Warning". We save us string length
this way in the actual calls.

While at it, shorten the calls in reserve_mc_sibling_devs().
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Yazen Ghannam <Yazen.Ghannam@amd.com>