firmware: microchip: fix UL_IAP lock check in mpfs_auto_update_state()

firmware: microchip: fix UL_IAP lock check in mpfs_auto_update_state()

To verify that Auto Update is possible, the mpfs_auto_update_state()
function performs a "Query Security Service Request" to the system
controller.

Previously, the check was performed on the first element of the
response message, which was accessed using a 32-bit pointer. This
caused the bitwise operation to reference incorrect data, as the
response should be inspected at the byte level. Fixed this by casting
the response to a  u8 * pointer, ensuring the check correctly inspects
the appropriate byte of the response message.

Additionally, rename "UL_Auto Update" to "UL_IAP" to match the
PolarFire Family System Services User Guide.

Signed-off-by: Valentina Fernandez <valentina.fernandezalanis@microchip.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>