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.

BUG=b:185191942
TEST=builds

Change-Id: I95bc92f6c54c5bcdac1c522ca87054aaffed0f40
Signed-off-by: Anastasia Klimchuk <aklm@chromium.org>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/54169
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
diff --git a/nicrealtek.c b/nicrealtek.c
index 5454b63..2208179 100644
--- a/nicrealtek.c
+++ b/nicrealtek.c
@@ -86,7 +86,7 @@
 	if (register_shutdown(nicrealtek_shutdown, NULL))
 		return 1;
 
-	register_par_master(&par_master_nicrealtek, BUS_PARALLEL);
+	register_par_master(&par_master_nicrealtek, BUS_PARALLEL, NULL);
 
 	return 0;
 }