flashchips.c: mark GD25Q256D as TESTED_OK_PREW

Tested read/write/erase/verify with FT232H programmer.

Change-Id: Ia7d52b69eb571113fe3c60ec9a139ee67180509b
Signed-off-by: Nikolai Artemiev <nartemiev@google.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/51735
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/flashchips.c b/flashchips.c
index 1e0c489..2f87515 100644
--- a/flashchips.c
+++ b/flashchips.c
@@ -6669,7 +6669,7 @@
 		.total_size	= 32768,
 		.page_size	= 256,
 		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_4BA_WREN,
-		.tested		= TEST_UNTESTED,
+		.tested		= TEST_OK_PREW,
 		.probe		= probe_spi_rdid,
 		.probe_timing	= TIMING_ZERO,
 		.block_erasers	=