[Backport v2.6-branch] Microchip: XEC GPIO driver interrupt enable part 2

Fixes issue #34879
This PR updates previous PR's 37138 and 37139.
Refer to issue 34879 for information from MCHP HW
designers. A delay after enabling interrupts is a
more appropriate work-around than depending upon
behavior of ARM DMB instruction.

Comparing to the original PR #37479 left changes only related to the
drivers/gpio/gpio_mchp_xec.c file
Tested  mec15xxevb_assy6853 board, no bugs GPIO detected.

Signed-off-by: Scott Worley <scott.worley@microchip.com>
Signed-off-by: Maksim Masalski <maksim.masalski@intel.com>