bfd/elf32-arm.c: Set st_value to zero for undefined symbols

Unless pointer_equality_needed is set then set st_value to be zero
for undefined symbols.

bfd/ChangeLog:

2014-03-20  Will Newton  <will.newton@linaro.org>

	PR ld/16715
	* elf32-arm.c (elf32_arm_check_relocs): Set
	pointer_equality_needed for absolute references within
	executable links.
	(elf32_arm_finish_dynamic_symbol): Set st_value to zero
	unless pointer_equality_needed is set.

ld/testsuite/ChangeLog:

2014-03-20  Will Newton  <will.newton@linaro.org>

	* ld-arm/ifunc-14.rd: Update symbol values.