ARM: OMAP2+: GPMC: fix device size setup

following statement can only change device size from 8-bit(0) to 16-bit(1),
but not vice versa:

regval |= GPMC_CONFIG1_DEVICESIZE(wval);

so as this field has 1 reserved bit, that could be used in future,
just clear both bits and then OR with the desired value
Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/gpmc.c

@@ -528,7 +528,13 @@ int gpmc_cs_configure(int cs, int cmd, int wval)
 
 	case GPMC_CONFIG_DEV_SIZE:
 		regval  = gpmc_cs_read_reg(cs, GPMC_CS_CONFIG1);
+
+		/* clear 2 target bits */
+		regval &= ~GPMC_CONFIG1_DEVICESIZE(3);
+
+		/* set the proper value */
 		regval |= GPMC_CONFIG1_DEVICESIZE(wval);
+
 		gpmc_cs_write_reg(cs, GPMC_CS_CONFIG1, regval);
 		break;