Staging: media: lirc: Use unsigned int instead unsigned

This patch fixes a WARNING: Prefer 'unsigned int' to bare use of
'unsigned', found by checkpatch.pl. By fixing this the types of the
parameters become more explicit.

Signed-off-by: Mihaela Muraru <mihaela.muraru21@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>