staging: rb8822be Change line not to end with '('

To comply with checkpatch.

CHECK: Lines should not end with a '('
+u8 rtl_mrate_idx_to_arfr_id(

Signed-off-by: Ricardo Silva <ricsilvs1@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>