target/ppc: Move VSX arithmetic and max/min insns to decodetree.

target/ppc: Move VSX arithmetic and max/min insns to decodetree.

Moving the following instructions to decodetree specification:

	x{s, v}{add, sub, mul, div}{s, d}p	: XX3-form
	xs{max, min}dp, xv{max, min}{s, d}p	: XX3-form

The changes were verfied by validating that the tcg ops generated by those
instructions remain the same, which were captured with the '-d in_asm,op' flag.

Signed-off-by: Chinmay Rath <rathc@linux.ibm.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>