binutils: Make some functions static in dwarf.c

binutils: Make some functions static in dwarf.c

The architecture specific register name initialisation routines no
longer need to be externally visible, so make them static.

binutils/ChangeLog:

	* dwarf.c (init_dwarf_regnames_i386): Make static.
	(init_dwarf_regnames_iamcu): Make static.
	(init_dwarf_regnames_x86_64): Make static.
	(init_dwarf_regnames_aarch64): Make static.
	(init_dwarf_regnames_s390): Make static.
	(init_dwarf_regnames_riscv): Make static.
	* dwarf.h (init_dwarf_regnames_i386): Delete declaration.
	(init_dwarf_regnames_iamcu): Delete declaration.
	(init_dwarf_regnames_x86_64): Delete declaration.
	(init_dwarf_regnames_aarch64): Delete declaration.
	(init_dwarf_regnames_s390): Delete declaration.
	(init_dwarf_regnames_riscv): Delete declaration.

Change-Id: I9e350f76f98f46e9e3dd88d502f2a2a83e44cb36