r300: Setup the back facing color bits correctly.

Apparently for back facing color to work you must set all 3 color bits; I guess
the hardware cannot handle them separately.

src/mesa/drivers/dri/r300/r300_emit.c

@@ -299,11 +299,12 @@ GLuint r300VAPOutputCntl0(GLcontext * ctx, GLuint OutputsWritten)
 	if (OutputsWritten & (1 << VERT_RESULT_COL1))
 		ret |= R300_VAP_OUTPUT_VTX_FMT_0__COLOR_1_PRESENT;
 
-	if (OutputsWritten & (1 << VERT_RESULT_BFC0))
-		ret |= (7 << 2);
-
-	if (OutputsWritten & (1 << VERT_RESULT_BFC1))
-		ret |= R300_VAP_OUTPUT_VTX_FMT_0__COLOR_3_PRESENT;
+	if (OutputsWritten & (1 << VERT_RESULT_BFC0)
+	    || OutputsWritten & (1 << VERT_RESULT_BFC1))
+		ret |=
+		    R300_VAP_OUTPUT_VTX_FMT_0__COLOR_1_PRESENT |
+		    R300_VAP_OUTPUT_VTX_FMT_0__COLOR_2_PRESENT |
+		    R300_VAP_OUTPUT_VTX_FMT_0__COLOR_3_PRESENT;
 
 #if 0
 	if (OutputsWritten & (1 << VERT_RESULT_FOGC)) ;