drm/amdgpu: Remove in_interrupt() usage in gfx_v9_0_kiq_read_clock()

gfx_v9_0_get_gpu_clock_counter() acquires a mutex_t lock and is the only
caller of gfx_v9_0_kiq_read_clock().
If it safe to acquire a mutex_t then gfx_v9_0_get_gpu_clock_counter() is
always invoked from preemptible context.

Remove in_interrupt() because it superfluous as it will always return
false.
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c

@@ -4172,7 +4172,7 @@ static uint64_t gfx_v9_0_kiq_read_clock(struct amdgpu_device *adev)
 	 *
 	 * also don't wait anymore for IRQ context
 	 * */
-	if (r < 1 && (amdgpu_in_reset(adev) || in_interrupt()))
+	if (r < 1 && (amdgpu_in_reset(adev)))
 		goto failed_kiq_read;
 
 	might_sleep();