programmer: Smoothen register_par_master API

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

Change-Id: I95bc92f6c54c5bcdac1c522ca87054aaffed0f40
Signed-off-by: Anastasia Klimchuk <aklm@chromium.org>
Original-Reviewed-on: https://review.coreboot.org/c/flashrom/+/54169
Original-Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/72201
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/satamv.c b/satamv.c
index 319ccce..e3970d7 100644
--- a/satamv.c
+++ b/satamv.c
@@ -148,7 +148,7 @@
 	/* 512 kByte with two 8-bit latches, and
 	 * 4 MByte with additional 3-bit latch. */
 	max_rom_decode.parallel = 4 * 1024 * 1024;
-	register_par_master(&par_master_satamv, BUS_PARALLEL);
+	register_par_master(&par_master_satamv, BUS_PARALLEL, NULL);
 
 	return 0;
 }