memory: emif: simplify locking with guard()

memory: emif: simplify locking with guard()

Simplify error handling (less gotos) over locks with guard().

The driver used file-scope variable 'irq_state' for storing IRQ state
with spin_lock_irqsave, so move it into respective local scopes.  This
should be equivalent, but more readable (less global variables).

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huwei.com>
Link: https://lore.kernel.org/r/20240823-b4-cleanup-h-guard-v1-2-01668915bd55@linaro.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>