target/ppc: use int128.h methods in vsubcuq

And also move the insn to decodetree and remove the now unused
avr_qw_not, avr_qw_cmpu, and avr_qw_add methods.

Signed-off-by: Matheus Ferst <matheus.ferst@eldorado.org.br>
Reviewed-by: VĂ­ctor Colombo <victor.colombo@eldorado.org.br>
Message-Id: <20220606150037.338931-8-matheus.ferst@eldorado.org.br>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
5 files changed