southbridge/dmp/vortex86ex/southbridge.c: Silence bitwise op warns

Silence some useless Clang warns in this case.

Change-Id: I202a85f7dec52c65d80e2bc56f7d9e4eb3e61d48
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/7696
Tested-by: build bot (Jenkins)
Reviewed-by: Vladimir Serbinenko <phcoder@gmail.com>
1 file changed