Compile gfxnvidia by default, but disallow write/erase

Corresponding to flashrom svn r1117.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Uwe Hermann <uwe@hermann-uwe.de>
diff --git a/gfxnvidia.c b/gfxnvidia.c
index 212f5b9..b0bf79b 100644
--- a/gfxnvidia.c
+++ b/gfxnvidia.c
@@ -82,6 +82,9 @@
 
 	buses_supported = CHIP_BUSTYPE_PARALLEL;
 
+	/* Write/erase doesn't work. */
+	programmer_may_write = 0;
+
 	return 0;
 }