spi25_statusreg,flashchips: add SR2 read/write support

This patch adds support for reading and writing the second status
register and enables it on a limited set of flash chips.

Chip support for RDSR2/WRSR2/extended WRSR is represented using feature
flags to be consistent with how other SPI capabilities are represented.

Tested: flashrom -{r,w,E}
Tested: flashrom --wp-{enable,disable,range,list,status} at end of patch series
Tested: logged SR2 read/write values during wp commands

Change-Id: I34a503b0958e8f2f22a2a993a6ea529eb46b41db
Signed-off-by: Nikolai Artemiev <nartemiev@google.com>
Original-Reviewed-on: https://review.coreboot.org/c/flashrom/+/58570
Original-Reviewed-by: Anastasia Klimchuk <aklm@chromium.org>
Original-Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/70965
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/flashchips.c b/flashchips.c
index c75e447..7ed2457 100644
--- a/flashchips.c
+++ b/flashchips.c
@@ -6279,7 +6279,7 @@
 		.total_size	= 16384,
 		.page_size	= 256,
 		/* OTP: 1024B total, 256B reserved; read 0x48; write 0x42, erase 0x44 */
-		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP,
+		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_WRSR_EXT,
 		.tested		= TEST_OK_PREW,
 		.probe		= probe_spi_rdid,
 		.probe_timing	= TIMING_ZERO,
@@ -6668,7 +6668,8 @@
 		.model_id	= GIGADEVICE_GD25Q256D,
 		.total_size	= 32768,
 		.page_size	= 256,
-		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_4BA_WREN,
+		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_4BA_WREN |
+				  FEATURE_WRSR_EXT | FEATURE_WRSR2,
 		.tested		= TEST_OK_PREW,
 		.probe		= probe_spi_rdid,
 		.probe_timing	= TIMING_ZERO,
@@ -6716,7 +6717,7 @@
 		.total_size	= 4096,
 		.page_size	= 256,
 		/* OTP: 1024B total, 256B reserved; read 0x48; write 0x42, erase 0x44 */
-		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP,
+		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_WRSR2,
 		.tested		= TEST_OK_PREW,
 		.probe		= probe_spi_rdid,
 		.probe_timing	= TIMING_ZERO,