drm/amd/amdgpu : Remove unused variable

Remove unused variable 'ret', and directly return 0.
Reviewed-by: NJunwei Zhang <Jerry.Zhang@amd.com>
Signed-off-by: NMuhammad Falak R Wani <falakreyaz@gmail.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

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

@@ -103,7 +103,6 @@ static void cik_ih_disable_interrupts(struct amdgpu_device *adev)
  */
 static int cik_ih_irq_init(struct amdgpu_device *adev)
 {
-	int ret = 0;
 	int rb_bufsz;
 	u32 interrupt_cntl, ih_cntl, ih_rb_cntl;
 	u64 wptr_off;
@@ -156,7 +155,7 @@ static int cik_ih_irq_init(struct amdgpu_device *adev)
 	/* enable irqs */
 	cik_ih_enable_interrupts(adev);
 
-	return ret;
+	return 0;
 }
 
 /**