drm/me/gsc: mei interrupt top half should be in irq disabled context

drm/me/gsc: mei interrupt top half should be in irq disabled context

MEI GSC interrupt comes from i915 or xe driver. It has top half and
bottom half. Top half is called from i915/xe interrupt handler. It
should be in irq disabled context.

With RT kernel(PREEMPT_RT enabled), by default IRQ handler is in
threaded IRQ. MEI GSC top half might be in threaded IRQ context.
generic_handle_irq_safe API could be called from either IRQ or
process context, it disables local IRQ then calls MEI GSC interrupt
top half.

This change fixes B580 GPU boot issue with RT enabled.

Fixes: e02cea83d32d ("drm/xe/gsc: add Battlemage support")
Tested-by: Baoli Zhang <baoli.zhang@intel.com>
Signed-off-by: Junxiao Chang <junxiao.chang@intel.com>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20251107033152.834960-1-junxiao.chang@intel.com
Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>
(cherry picked from commit 3efadf028783a49ab2941294187c8b6dd86bf7da)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>