Don't fudge p_vaddr when PHDR in segment

Don't fudge p_vaddr when PHDR in segment

RX does horrible fudges to PT_LOAD p_vaddr, that affect the testsuite
and mean the target won't support dynamic objects.  The latter
probably doesn't matter too much since RX is an embedded target, but
it's easy to stop some of the fudges in order to reduce special cases
for RX in the testsuite.  The changes make sense in isolation too.

bfd/
	* elf32-rx.c (elf32_rx_modify_program_headers): Don't adjust
	segments that include the ELF file header or program headers.
ld/
	* testsuite/ld-elf/flags1.d: Run for RX.
	* testsuite/ld-scripts/phdrs.exp: Likewise.
	* testsuite/ld-scripts/pr14962.d: Likewise.
	* testsuite/ld-scripts/pr14962-2.d: Likewise.