aspeed/scu: Fix W1C behavior

aspeed/scu: Fix W1C behavior

This models the clock write one to clear registers, and fixes up some
incorrect behavior in all of the write to clear registers.

There was also a typo in one of the register definitions.

Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-id: 20191119141211.25716-8-clg@kaod.org
[clg: checkpatch.pl fixes ]
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>