drm/i915: pass dev_priv explicitly to DSPGAMC

Avoid the implicit dev_priv local variable use, and pass dev_priv
explicitly to the DSPGAMC register macro.
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/542455204f62182a46fa2cb16ad6b0648c72f612.1716469091.git.jani.nikula@intel.comSigned-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/display/i9xx_plane_regs.h

@@ -84,7 +84,7 @@
 #define DSPSURFLIVE(dev_priv, plane)		_MMIO_PIPE2(dev_priv, plane, _DSPASURFLIVE)
 
 #define _DSPAGAMC				0x701E0 /* pre-g4x */
-#define DSPGAMC(plane, i)			_MMIO_PIPE2(dev_priv, plane, _DSPAGAMC + (5 - (i)) * 4) /* plane C only, 6 x u0.8 */
+#define DSPGAMC(dev_priv, plane, i)		_MMIO_PIPE2(dev_priv, plane, _DSPAGAMC + (5 - (i)) * 4) /* plane C only, 6 x u0.8 */
 
 /* CHV pipe B primary plane */
 #define _PRIMPOS_A		0x60a08