flashchips: Fix 4BA advertisement for dummy chip

The dummyflasher only supports the native 4BA read and write
commands, so only advertise these.

Change-Id: Ia7340835ce1680d197f250bdb5990ab2ffe3671f
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/54068
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
diff --git a/flashchips.c b/flashchips.c
index 6482f67..007bcc9 100644
--- a/flashchips.c
+++ b/flashchips.c
@@ -19569,7 +19569,7 @@
 		.model_id	= PROGDEV_ID,
 		.total_size	= 64,  /* This size is set temporarily */
 		.page_size	= 256,
-		.feature_bits	= FEATURE_4BA,
+		.feature_bits	= FEATURE_4BA_READ | FEATURE_4BA_WRITE,
 		.tested		= TEST_OK_PREW,
 		.probe		= probe_variable_size,
 		.block_erasers	=