[AArch64] Revert wrong commit of "Improve TLS Descriptor pattern to release RTL loop...

[AArch64] Revert wrong commit of "Improve TLS Descriptor pattern to release RTL loop IV opt"

Revert the wrong commit of

  2015-08-06    Ramana Radhakrishnan  <ramana.radhakrishnan@arm.com>
	      Jiong Wang  <jiong.wang@arm.com>

	* config/aarch64/aarch64.d (tlsdesc_small_pseudo_<mode>): New pattern.
	* config/aarch64/aarch64.h (reg_class): New enumeration FIXED_REG0.
	(REG_CLASS_NAMES): Likewise.
	(REG_CLASS_CONTENTS): Likewise.
	* config/aarch64/aarch64.c (aarch64_class_max_nregs): Likewise.
	(aarch64_register_move_cost): Likewise.
	(aarch64_load_symref_appropriately): Invoke the new added pattern if
	possible.
	* config/aarch64/constraints.md (Uc0): New constraint.

From-SVN: r226756