Implemented Get/SetDeviceGammaRamp.

diff --git a/dlls/wineps/init.c b/dlls/wineps/init.c
index 5905f01..70028d2 100644
--- a/dlls/wineps/init.c
+++ b/dlls/wineps/init.c
@@ -58,6 +58,7 @@
     NULL,                            /* pFrameRgn */
     PSDRV_GetCharWidth,              /* pGetCharWidth */
     NULL,                            /* pGetDCOrgEx */
+    NULL,                            /* pGetDeviceGammaRamp */
     NULL,                            /* pGetPixel */
     NULL,                            /* pGetPixelFormat */
     PSDRV_GetTextExtentPoint,        /* pGetTextExtentPoint */
@@ -94,6 +95,7 @@
     PSDRV_SetBkColor,                /* pSetBkColor */
     NULL,                            /* pSetBkMode */
     PSDRV_SetDeviceClipping,         /* pSetDeviceClipping */
+    NULL,                            /* pSetDeviceGammaRamp */
     NULL,                            /* pSetDIBitsToDevice */
     NULL,                            /* pSetMapMode (optional) */
     NULL,                            /* pSetMapperFlags */