RISC-V: Fix comment typos

RISC-V: Fix comment typos

This fixes most of the typos I found when reading various parts of the RISC-V
backend.

gcc/ChangeLog:

	* config/riscv/arch-canonicalize: Fix typos in comments.
	* config/riscv/autovec.md: Ditto.
	* config/riscv/riscv-avlprop.cc (avl_can_be_propagated_p): Ditto.
	(pass_avlprop::get_vlmax_ta_preferred_avl): Ditto.
	* config/riscv/riscv-modes.def (ADJUST_FLOAT_FORMAT): Ditto.
	(VLS_MODES): Ditto.
	* config/riscv/riscv-opts.h (TARGET_ZICOND_LIKE): Ditto.
	(enum rvv_vector_bits_enum): Ditto.
	* config/riscv/riscv-protos.h (enum insn_flags): Ditto.
	(enum insn_type): Ditto.
	* config/riscv/riscv-sr.cc (riscv_sr_match_epilogue): Ditto.
	* config/riscv/riscv-string.cc (expand_block_move): Ditto.
	* config/riscv/riscv-v.cc (rvv_builder::is_repeating_sequence): Ditto.
	(rvv_builder::single_step_npatterns_p): Ditto.
	(calculate_ratio): Ditto.
	(expand_const_vector): Ditto.
	(shuffle_merge_patterns): Ditto.
	(shuffle_compress_patterns): Ditto.
	(expand_select_vl): Ditto.
	* config/riscv/riscv-vector-builtins-functions.def (REQUIRED_EXTENSIONS): Ditto.
	* config/riscv/riscv-vector-builtins-shapes.h: Ditto.
	* config/riscv/riscv-vector-builtins.cc (function_builder::add_function): Ditto.
	(resolve_overloaded_builtin): Ditto.
	* config/riscv/riscv-vector-builtins.def (vbool1_t): Ditto.
	(vuint8m8_t): Ditto.
	(vuint16m8_t): Ditto.
	(vfloat16m8_t): Ditto.
	(unsigned_vector): Ditto.
	* config/riscv/riscv-vector-builtins.h (enum required_ext): Ditto.
	* config/riscv/riscv-vector-costs.cc (get_store_value): Ditto.
	(costs::analyze_loop_vinfo): Ditto.
	(costs::add_stmt_cost): Ditto.
	* config/riscv/riscv.cc (riscv_build_integer): Ditto.
	(riscv_vector_type_p): Ditto.
	* config/riscv/thead.cc (th_mempair_output_move): Ditto.
	* config/riscv/thead.md: Ditto.
	* config/riscv/vector-iterators.md: Ditto.
	* config/riscv/vector.md: Ditto.
	* config/riscv/zc.md: Ditto.

Signed-off-by: Patrick O'Neill <patrick@rivosinc.com>