SST49FL040B: add unlocking

The datasheet says there's a set of registers in the 4Mbit before the
flash memory.  The block locking registers are aligned on 64K
boundaries, plus 2.

Write/erase sucessful on a system it failed before:
  http://www.flashrom.org/pipermail/flashrom/2010-August/004432.html



Corresponding to flashrom svn r1144.
Signed-off-by: Joshua Roys <roysjosh@gmail.com>
Acked-by: Michael Karcher <flashrom@mkarcher.dialup.fu-berlin.de>

flashchips.c

@@ -5651,8 +5651,8 @@ struct flashchip flashchips[] = {
 		.model_id	= SST_49LF040B,
 		.total_size	= 512,
 		.page_size	= 64 * 1024,
-		.feature_bits	= FEATURE_EITHER_RESET,
-		.tested		= TEST_OK_PR,
+		.feature_bits	= FEATURE_EITHER_RESET | FEATURE_REGISTERMAP,
+		.tested		= TEST_OK_PREW,
 		.probe		= probe_jedec,
 		.probe_timing	= 1,		/* 150ns */
 		.block_erasers	=
@@ -5668,6 +5668,7 @@ struct flashchip flashchips[] = {
 				.block_erase = NULL,
 			}
 		},
+		.unlock		= unlock_82802ab,
 		.write		= write_jedec_1,
 		.read		= read_memmapped,
 	},