In the include/elf/arc.h there are two constants that mask out the
machine architecture field. One is used lots (EF_ARC_MACH_MSK), the
other is used only once (EF_ARC_MACH). Remove EF_ARC_MACH.
bfd/ChangeLog:
* elf32-arc.c (arc_elf_final_write_processing): Switch to using
EF_ARC_MACH_MSK.
include/ChangeLog:
* elf/arc.h (EF_ARC_MACH): Delete.
(EF_ARC_MACH_MSK): Remove out of date comment.