OMAP: VP: Explicitly mask VPVOLTAGE field

Reading the VPVOLTAGE field of PRM_VP_*_VOLTAGE registers currently
relies on a u32 -> u8 conversion to mask off the FORCEUPDATEWAIT field
in the upper bits.  Make this explicit using the mask symbol
already defined, added as a new field in struct omap_vp_common.

Signed-off-by: Todd Poynor <toddpoynor@google.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>
diff --git a/arch/arm/mach-omap2/vp3xxx_data.c b/arch/arm/mach-omap2/vp3xxx_data.c
index d429c44..260c554 100644
--- a/arch/arm/mach-omap2/vp3xxx_data.c
+++ b/arch/arm/mach-omap2/vp3xxx_data.c
@@ -51,6 +51,8 @@
 	.vlimitto_vddmin_shift = OMAP3430_VDDMIN_SHIFT,
 	.vlimitto_vddmax_shift = OMAP3430_VDDMAX_SHIFT,
 	.vlimitto_timeout_shift = OMAP3430_TIMEOUT_SHIFT,
+	.vpvoltage_mask = OMAP3430_VPVOLTAGE_MASK,
+
 	.ops = &omap3_vp_ops,
 };