usb: Drop commas after SoC match table sentinels

It does not make sense to have a comma after a sentinel, as any new
elements must be added before the sentinel.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/5cae409f647272a5679291ebc0000bfeccc14160.1646311762.git.geert+renesas@glider.be


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>