programmer: Smoothen register_spi_master() API

It was impossible to register a const struct spi_master that would
point to dynamically allocated `data`. Fix that so that we won't
have to create more mutable globals.

Change-Id: I0c753b3db050fb87d4bbe2301a7ead854f28456f
Signed-off-by: Nico Huber <nico.h@gmx.de>
Original-Reviewed-on: https://review.coreboot.org/c/flashrom/+/54066
Original-Reviewed-by: Anastasia Klimchuk <aklm@chromium.org>
Original-Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/72179
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/stlinkv3_spi.c b/stlinkv3_spi.c
index 68790cf..50b5c85 100644
--- a/stlinkv3_spi.c
+++ b/stlinkv3_spi.c
@@ -507,7 +507,7 @@
 	if (register_shutdown(stlinkv3_spi_shutdown, NULL))
 		goto init_err_cleanup_exit;
 
-	if (register_spi_master(&spi_programmer_stlinkv3))
+	if (register_spi_master(&spi_programmer_stlinkv3, NULL))
 		return 1; /* shutdown function does cleanup */
 
 	return 0;