i386: Issue an error on non-PIC call to IFUNC in PIC object

i386: Issue an error on non-PIC call to IFUNC in PIC object

On i386, IFUNC function must be called via PLT.  Since PLT in PIC
object uses EBX register, R_386_PLT32 relocation must be used to
call IFUNC function even when IFUNC function is defined locally.
Linker should issue an error when R_386_PC32 relocation is used
to call IFUNC function.

Since PR ld/19784 tests doesn't use PLT relocation to local IFUNC
function, they are moved to the x86-64 test directory.

bfd/

	PR ld/14961
	PR ld/20515
	* elf32-i386.c (elf_i386_check_relocs): Issue an error when
	R_386_PC32 relocation is used to call IFUNC function in PIC
	object.

ld/

	PR ld/14961
	PR ld/20515
	* testsuite/ld-i386/i386.exp: Run pr20515.
	* testsuite/ld-i386/pr20515.d: New file.
	* testsuite/ld-i386/pr20515.s: Likewise.
	* testsuite/ld-ifunc/ifunc-14a.s: Use R_386_PLT32 to call IFUNC
	function.
	* testsuite/ld-ifunc/ifunc-14c.s: Likewise.
	* testsuite/ld-ifunc/ifunc-2-i386.s: Likewise.
	* testsuite/ld-ifunc/ifunc-2-local-i386.s: Likewise.
	* testsuite/ld-ifunc/ifunc.exp: Move PR ld/19784 tests to ...
	* testsuite/ld-x86-64/x86-64.exp: Here.
	* testsuite/ld-ifunc/pr19784a.c: Moved to ...
	* testsuite/ld-x86-64/pr19784a.c: Here.
	* testsuite/ld-ifunc/pr19784b.c: Moved to ...
	* testsuite/ld-x86-64/pr19784b.c: Here.
	* testsuite/ld-ifunc/pr19784c.c: Moved to ...
	* testsuite/ld-x86-64/pr19784c.c: Here.