target/ppc: Move div/mod fixed-point insns (64 bits operands) to decodetree.

target/ppc: Move div/mod fixed-point insns (64 bits operands) to decodetree.

Moving the below instructions to decodetree specification :

	divd[u, e, eu][o][.]	: XO-form
	mod{sd, ud}		: X-form

With this patch, all the fixed-point arithmetic instructions have been
moved to decodetree.
The changes were verified by validating that the tcg ops generated by those
instructions remain the same, which were captured using the '-d in_asm,op' flag.
Also, remaned do_divwe method in fixedpoint-impl.c.inc to do_dive because it is
now used to divide doubleword operands as well, and not just words.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Chinmay Rath <rathc@linux.ibm.com>
[np: 32-bit compile fix]
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>