Rename REG_CFA_TOGGLE_RA_MANGLE to REG_CFA_NEGATE_RA_STATE

Rename REG_CFA_TOGGLE_RA_MANGLE to REG_CFA_NEGATE_RA_STATE

The current name REG_CFA_TOGGLE_RA_MANGLE is not representative of what
it really is, i.e. a register to represent several states, not only a
binary one. Same for dwarf2out_frame_debug_cfa_toggle_ra_mangle.

gcc/ChangeLog:

	* combine-stack-adj.cc
	(no_unhandled_cfa): Rename.
	* config/aarch64/aarch64.cc
	(aarch64_expand_prologue): Rename.
	(aarch64_expand_epilogue): Rename.
	* dwarf2cfi.cc
	(dwarf2out_frame_debug_cfa_toggle_ra_mangle): Rename this...
	(dwarf2out_frame_debug_cfa_negate_ra_state): To this.
	(dwarf2out_frame_debug): Rename.
	* reg-notes.def (REG_CFA_NOTE): Rename REG_CFA_TOGGLE_RA_MANGLE.