Subtract GOT base only with a base register

Subtract GOT base only with a base register

When relocating R_386_GOT32 in "op $0, bar@GOT", we shouldn't subtract
GOT base without a base register and we should disallow it without a
base register for PIC.

bfd/

	PR ld/20244
	* elf32-i386.c (elf_i386_relocate_section): When relocating
	R_386_GOT32, return error without a base register for PIC and
	subtract the .got.plt section address only with a base register.

ld/

	PR ld/20244
	* testsuite/ld-i386/i386.exp: Run pr20244-1a and pr20244-1b.
	* testsuite/ld-i386/pr20244-1.s: New file.
	* testsuite/ld-i386/pr20244-1a.d: Likewise.
	* testsuite/ld-i386/pr20244-1b.d: Likewise.
	* testsuite/ld-i386/pr20244-1c.d: Likewise.