drm/i915/icl: Define missing bitfield for shortplug reg

This patch define missing bitfield for shortplug ctl ddi
register which will be used for ICL DSI GPIO programming.
Signed-off-by: Madhav Chauhan <madhav.chauhan@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/4b9feb75eb6c303556b91c8a23c505a4593a99a1.1543500286.git.jani.nikula@intel.com

drivers/gpu/drm/i915/i915_reg.h

@@ -7751,6 +7751,7 @@ enum {
 #define   ICP_DDIB_HPD_LONG_DETECT		(2 << 4)
 #define   ICP_DDIB_HPD_SHORT_LONG_DETECT	(3 << 4)
 #define   ICP_DDIA_HPD_ENABLE			(1 << 3)
+#define   ICP_DDIA_HPD_OP_DRIVE_1		(1 << 2)
 #define   ICP_DDIA_HPD_STATUS_MASK		(3 << 0)
 #define   ICP_DDIA_HPD_NO_DETECT		(0 << 0)
 #define   ICP_DDIA_HPD_SHORT_DETECT		(1 << 0)