ARM: OMAP2+: Variable "reg" in function omap4_dsi_mux_pads() could be uninitialized

In function omap4_dsi_mux_pads(), local variable "reg" could
be uninitialized if function regmap_read() returns -EINVAL.
However, it will be used directly in the later context, which
is potentially unsafe.
Signed-off-by: Yizhuo <yzhai003@ucr.edu>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/display.c

@@ -83,6 +83,7 @@ static int omap4_dsi_mux_pads(int dsi_id, unsigned lanes)
 	u32 enable_mask, enable_shift;
 	u32 pipd_mask, pipd_shift;
 	u32 reg;
+	int ret;
 
 	if (dsi_id == 0) {
 		enable_mask = OMAP4_DSI1_LANEENABLE_MASK;
@@ -98,7 +99,11 @@ static int omap4_dsi_mux_pads(int dsi_id, unsigned lanes)
 		return -ENODEV;
 	}
 
-	regmap_read(omap4_dsi_mux_syscon, OMAP4_DSIPHY_SYSCON_OFFSET, &reg);
+	ret = regmap_read(omap4_dsi_mux_syscon,
+					  OMAP4_DSIPHY_SYSCON_OFFSET,
+					  &reg);
+	if (ret)
+		return ret;
 
 	reg &= ~enable_mask;
 	reg &= ~pipd_mask;