[Patch ARM] Fix PR target/81863

[Patch ARM] Fix PR target/81863

This has been in my patch stack for quite some time. The problem here
was that we weren't handling arm_word_relocations in
arm_valid_symbolic_address and is the surest fix for this
for GCC8 and GCC7.

Regression tested on arm-none-linux-gnueabihf . Applying to
trunk and backporting to GCC-7 in a day or so.

regards
Ramana

2018-03-27  Ramana Radhakrishnan  <ramana.radhakrishnan@arm.com>

	PR target/81863
	* config/arm/arm.c (arm_valid_symbolic_address): Handle arm_word_relocations

2018-03-27  Ramana Radhakrishnan  <ramana.radhakrishnan@arm.com>

	PR target/81863
	* gcc.target/arm/pr81863.c: New test.

From-SVN: r258886