omxil: Factorize samsung decoder quirk identification to a separate function

Previously, we tried to see if the samsung decoder name followed
a certain pattern (ending .Decoder, for good decoders, assuming
we should ignore the padding specified by all other samsung
decoders). This simple pattern didn't turn out to apply for some
other deocders, so instead explicitly list the components that
we know we should ignore the specified padding values.

Also refactor the same check from both the omxil and mediacodec
files into one utility function.

Signed-off-by: Martin Storsjö <martin@martin.st>