Check verify flag in prepare_flash_access before erase operation

The last argument in `prepare_flash_access` function indicates
whether verify operation was requested. This information is
in the flag `verify_after_write` in flash context, so lets pass
it to the function.

Previously, the last argument which is called `verify_it`
was always `false`. This hasn't been detected because in the
current implementation of `prepare_flash_access`,
`verify_it` is always checked together with `erase_it`, the
latter was passed always true.

`verify_it` being false is wrong because we have a flag to decide
about verification. Also this false value contradicts reality,
because erase operation ignores the flag and always verifies
(this has always been the case even with earlier implementations
of erase logic).

Additional context is in the next commit and ticket
https://ticket.coreboot.org/issues/520

Change-Id: Idd7526084e4942b7adbbab57a62f7de84b4a4bb5
Signed-off-by: Anastasia Klimchuk <aklm@flashrom.org>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/88733
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

flashrom.c

@@ -1890,7 +1890,7 @@ void finalize_flash_access(struct flashctx *const flash)
 
 int flashrom_flash_erase(struct flashctx *const flashctx)
 {
-	if (prepare_flash_access(flashctx, false, false, true, false))
+	if (prepare_flash_access(flashctx, false, false, true, flashctx->flags.verify_after_write))
 		return 1;
 
 	const int ret = erase_by_layout(flashctx);