Remove unnecessary ELF_MINPAGESIZE defines

The idea of this patch is to make it easy to see which targets (just
sparc) have ELF_MINPAGESIZE != ELF_COMMONPAGESIZE.

	* elf32-arm.c (ELF_MINPAGESIZE): Don't define.
	* elf32-metag.c: Likewise.
	* elfnn-aarch64.c: Likewise.
	* elf64-x86-64.c: Likewise.  Also don't redefine a bunch of other
	macros for l1om elf64-target.h use that are unchanged from default.