pinctrl: aspeed: Clarify comment about strapping W1C

pinctrl: aspeed: Clarify comment about strapping W1C

Writes of 1 to SCU7C clear set bits in SCU70, the hardware strapping
register. The information was correct if you squinted while reading, but
hopefully switching the order of the registers as listed conveys it
better.

Cc: Johnny Huang <johnny_huang@aspeedtech.com>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20190628023838.15426-7-andrew@aj.id.au
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>