pinctrl: intel: refine intel_config_set_pull() function

Improve intel_config_set_pull() implementation in Intel pinctrl driver by:

- Reducing scope of spinlock by moving unneeded operations out of it.
- Utilizing temporary variables for common operations.
- Limiting IO operations to positive cases.

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