Arm/AArch64: Use a single set of Arm register set size defines

Arm/AArch64: Use a single set of Arm register set size defines

Both targets were using a mixture of defines and hardcoded values.
Add a standard set in arch/arm.h and use throughout, ensuring that
none of the existing sizes change.

No functionality changes.

gdb/ChangeLog:

	* aarch32-linux-nat.h (VFP_REGS_SIZE): Remove define.
	* aarch64-linux-nat.c (fetch_fpregs_from_thread)
	(store_fpregs_to_thread)
	(aarch64_linux_nat_target::read_description): Use ARM_VFP3_REGS_SIZE.
	* arch/arm.h (IWMMXT_VEC_REGISTER_SIZE, ARM_CORE_REGS_SIZE)
	(ARM_FP_REGS_SIZE, ARM_VFP2_REGS_SIZE, ARM_VFP3_REGS_SIZE)
	(IWMMXT_REGS_SIZE): Add define.
	* arm-linux-nat.c (IWMMXT_REGS_SIZE): Remove define.
	(fetch_vfp_regs, store_vfp_regs)
	(arm_linux_nat_target::read_description): Use ARM_VFP3_REGS_SIZE.
	* arm-tdep.c (arm_register_g_packet_guesses): Use new defines.

gdb/gdbserver/ChangeLog:

	* linux-aarch32-low.c (arm_read_description, arm_regsets): Use new
	defines.
	* linux-arm-low.c (arm_read_description, arm_regsets): Likewise.