opencv: support machines based on oe-core tune-corei7.inc

oe-core tune-corei7.inc enables -msse4.2 (rather than -msse3, which is
only enabled by tune-core2.inc). Add test for -msse4.2 to ensure that
SSE is enabled for machines based on tune-corei7.inc (also add a test
for -msse4.1 for completeness).

Signed-off-by: Andre McCurdy <armccurdy@gmail.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>