ARM: shmobile: Drop commas after dt_compat 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/ab4acc22eebb96a0747eb301c878b24b1200736a.1646311825.git.geert+renesas@glider.be