drivers: espi: xec: Fix eSPI frequency override during IO selection
drivers: espi: xec: Fix eSPI frequency override during IO selection

Fix incorrect register update that results in unintentionally
in default eSPI frequency (20MHz) whenver IO mode is changed.

Signed-off-by: Jose Alberto Meza <93346bcba00086196ffe58e37d7adff1143c3f07@intel.com>

zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,nashif/zephyr,finikorg/zephyr,galak/zephyr,galak/zephyr,Vudentz/zephyr,Vudentz/zephyr,galak/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,nashif/zephyr,Vudentz/zephyr,Vudentz/zephyr,Vudentz/zephyr,galak/zephyr,galak/zephyr,nashif/zephyr,nashif/zephyr