mfd: OLPC: Clean up names to match what OLPC actually uses

The cs5535-pms cell doesn't actually need to be cloned, so we can drop that
and simply have the olpc-xo1.c driver use "cs5535-pms" directly.

Also, rename the cs5535-acpi clones to what we actually use for the (currently
out-of-tree) SCI driver.  In the process, that fixes a subtle bug in
olpc-xo1.c which broke powerdown on XO-1s.. olpc-xo1-ac-acpi was a typo, not
something that actually existed.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Signed-off-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>