i915: Enable preemption for schedule_timeout call in intel_vblank_evade

Fixes following panic:

panic: mi_switch: switch in a critical section
cpuid = 0
time = 1755345737
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe01121f4620
vpanic() at vpanic+0x136/frame 0xfffffe01121f4750
panic() at panic+0x43/frame 0xfffffe01121f47b0
mi_switch() at mi_switch+0x1b7/frame 0xfffffe01121f47d0
sleepq_switch() at sleepq_switch+0x109/frame 0xfffffe01121f4810
sleepq_timedwait() at sleepq_timedwait+0x4b/frame 0xfffffe01121f4850
linux_add_to_sleepqueue() at linux_add_to_sleepqueue+0xf1/frame 0xfffffe01121f48a0
linux_schedule_timeout() at linux_schedule_timeout+0x6a/frame 0xfffffe01121f48d0
intel_vblank_evade() at intel_vblank_evade+0x147/frame 0xfffffe01121f4940
intel_legacy_cursor_update() at intel_legacy_cursor_update+0x2d8/frame 0xfffffe01121f49e0
drm_mode_cursor_common() at drm_mode_cursor_common+0x38f/frame 0xfffffe01121f4b10
drm_mode_cursor_ioctl() at drm_mode_cursor_ioctl+0x36/frame 0xfffffe01121f4b50
drm_ioctl_kernel() at drm_ioctl_kernel+0xa3/frame 0xfffffe01121f4b90
drm_ioctl() at drm_ioctl+0x2de/frame 0xfffffe01121f4c80
linux_file_ioctl() at linux_file_ioctl+0x301/frame 0xfffffe01121f4ce0
kern_ioctl() at kern_ioctl+0x286/frame 0xfffffe01121f4d40
sys_ioctl() at sys_ioctl+0x12f/frame 0xfffffe01121f4e00
amd64_syscall() at amd64_syscall+0x169/frame 0xfffffe01121f4f30
fast_syscall_common() at fast_syscall_common+0xf8/frame 0xfffffe01121f4f30

Author: wulf7

drivers/gpu/drm/i915/display/intel_vblank.c

@@ -684,12 +684,16 @@ int intel_vblank_evade(struct intel_vblank_evade_ctx *evade)
 
 #ifdef __linux__
 		local_irq_enable();
+#elif defined(__FreeBSD__)
+		preempt_enable();
 #endif
 
 		timeout = schedule_timeout(timeout);
 
 #ifdef __linux__
 		local_irq_disable();
+#elif defined(__FreeBSD__)
+		preempt_disable();
 #endif
 	}