ARM: mach-shmobile: sh73a0 CPGA fix for KEYSC

Fix the sh73a0 KEYSC clock control by adding MSTP403
to mstp_clks[]. Use KEYSC instead of KEYSC0 in comments.

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>