[AArch64] Delete aarch64_symbol_context which is not used

[AArch64] Delete aarch64_symbol_context which is not used

2015-09-24  Jiong Wang  <jiong.wang@arm.com>

	* config/aarch64/aarch64-protos.h (aarch64_symbol_context): Delete.
	* config/aarch64/aarch64.c (aarch64_expand_mov_immediate): Likewise.
	(aarch64_cannot_force_const_mem): Likewise.
	(aarch64_classify_address): Likewise.
	(aarch64_classify_symbolic_expression): Likewise.
	(aarch64_print_operand): Likewise.
	(aarch64_classify_symbol): Likewise.
	(aarch64_mov_operand_p): Likewise.
	* config/aarch64/predicates.md (aarch64_valid_symref): Likewise.
	(aarch64_mov_operand): Likewise.

From-SVN: r228092