Fix spelling mistakes.

opcodes	* nfp-dis.c: Fix spelling mistake.

ld	* emultempl/aarch64elf.em: Fix spelling mistake.
	* emultempl/avrelf.em: Likewise.
	* emultempl/elf32.em: Likewise.

binutils* doc/binutils.texi: Fix spelling mistakes.
	* README--how-to-make-a-release: Likewise.