parallel.c: Consoldiate parallel master registration logic

This is analogous to spi.c and opaque.c however parallel
logic was previously never consoldiated.

This free's up flashrom.c from namespace pollution.

Tested: builds with both make and meson.

Change-Id: Ie08e2e6c51ccef5281386bf7e3df439b91573974
Signed-off-by: Edward O'Callaghan <quasisec@google.com>
Original-Reviewed-on: https://review.coreboot.org/c/flashrom/+/66651
Original-Reviewed-by: Thomas Heijligen <src@posteo.de>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/72349
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/Makefile b/Makefile
index 74bacaa..78b4d43 100644
--- a/Makefile
+++ b/Makefile
@@ -387,7 +387,7 @@
 ###############################################################################
 # Library code.
 
-LIB_OBJS = libflashrom.o layout.o flashrom.o udelay.o programmer.o programmer_table.o \
+LIB_OBJS = libflashrom.o layout.o flashrom.o udelay.o parallel.o programmer.o programmer_table.o \
 	helpers.o helpers_fileio.o ich_descriptors.o fmap.o platform/endian_$(ENDIAN).o platform/memaccess.o