drm/omap: dsi: Rework and remove a few unused variables

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/omapdrm/dss/dsi.c: In function ‘_dsi_print_reset_status’:
 drivers/gpu/drm/omapdrm/dss/dsi.c:1131:6: warning: variable ‘l’ set but not used [-Wunused-but-set-variable]
 drivers/gpu/drm/omapdrm/dss/dsi.c: In function ‘dsi_update’:
 drivers/gpu/drm/omapdrm/dss/dsi.c:3943:10: warning: variable ‘dh’ set but not used [-Wunused-but-set-variable]
 drivers/gpu/drm/omapdrm/dss/dsi.c:3943:6: warning: variable ‘dw’ set but not used [-Wunused-but-set-variable]

Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201105144517.1826692-9-lee.jones@linaro.org

drivers/gpu/drm/omapdrm/dss/dsi.c

@@ -1128,13 +1128,12 @@ static void dsi_runtime_put(struct dsi_data *dsi)
 
 static void _dsi_print_reset_status(struct dsi_data *dsi)
 {
-	u32 l;
 	int b0, b1, b2;
 
 	/* A dummy read using the SCP interface to any DSIPHY register is
 	 * required after DSIPHY reset to complete the reset of the DSI complex
 	 * I/O. */
-	l = dsi_read_reg(dsi, DSI_DSIPHY_CFG5);
+	dsi_read_reg(dsi, DSI_DSIPHY_CFG5);
 
 	if (dsi->data->quirks & DSI_QUIRK_REVERSE_TXCLKESC) {
 		b0 = 28;
@@ -3940,7 +3939,6 @@ static int dsi_update(struct omap_dss_device *dssdev, int channel,
 		void (*callback)(int, void *), void *data)
 {
 	struct dsi_data *dsi = to_dsi_data(dssdev);
-	u16 dw, dh;
 
 	dsi_perf_mark_setup(dsi);
 
@@ -3949,11 +3947,8 @@ static int dsi_update(struct omap_dss_device *dssdev, int channel,
 	dsi->framedone_callback = callback;
 	dsi->framedone_data = data;
 
-	dw = dsi->vm.hactive;
-	dh = dsi->vm.vactive;
-
 #ifdef DSI_PERF_MEASURE
-	dsi->update_bytes = dw * dh *
+	dsi->update_bytes = dsi->vm.hactive * dsi->vm.vactive *
 		dsi_get_pixel_size(dsi->pix_fmt) / 8;
 #endif
 	dsi_update_screen_dispc(dsi);