Support for the 39sf020

Corresponding to coreboot v1 svn r544.
diff --git a/flash_rom.c b/flash_rom.c
index 171fe3e..24b07a7 100644
--- a/flash_rom.c
+++ b/flash_rom.c
@@ -48,7 +48,7 @@
     {"SST28SF040A", SST_ID,     SST_28SF040,  NULL, 512, 256,
      probe_28sf040, erase_28sf040, write_28sf040},
     {"SST39SF020A", SST_ID,     SST_39SF020,  NULL, 256, 4096,
-     probe_jedec, erase_jedec, write_39sf020},
+     probe_39sf020, erase_39sf020, write_39sf020},
     {"W29C020C",    WINBOND_ID, W_29C020C,    NULL, 256, 128,
      probe_jedec,   erase_jedec,   write_jedec},
     {NULL,}