pinctrl: cherryview: Avoid duplicated I/O

In some cases we already read the value from the register followed
by a reading of it again for other purposes, but the both reads
are under the lock and bits we are insterested in are not going
to change (they are not volatile from HW perspective). Hence, no
need to read the same register twice.

Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>