flashchips,spi25: Replace .wrea_override with FEATURE_4BA_EAR_1716

There are two competing sets of instructions to access the extended
address register of 4BA SPI chips. Some chips even support both sets.

So far, we assumed the 0xc5/0xc8 instructions by default and allowed
to override the write instructions with the `.wrea_override` field.
This has some disadvantages:

* The additional field is easily overlooked. So when adding a new
  flash chip, one might assume only 0xc5/0xc8 are supported.

* We cannot describe flash chips completely that allow both
  instructions (and some programmers may be picky about which
  instructions can be used).

Therefore, replace the `.wrea_override` field with a feature flag.

Signed-off-by: Nico Huber <nico.h@gmx.de>
Change-Id: I6d82f24898acd0789203516a7456fd785907bc10
Ticket: https://ticket.coreboot.org/issues/357
Reviewed-on: https://review.coreboot.org/c/flashrom/+/64636
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Thomas Heijligen <src@posteo.de>

dediprog.c

@@ -416,7 +416,7 @@ static int prepare_rw_cmd(
 			}
 		}
 	} else {
-		if (flash->chip->feature_bits & FEATURE_4BA_EAR_C5C8) {
+		if (flash->chip->feature_bits & FEATURE_4BA_EAR_ANY) {
 			if (spi_set_extended_address(flash, start >> 24))
 				return 1;
 		} else if (start >> 24) {