target/ppc: Remove extra space from s128 field in ppc_vsr_t

Very trivial rogue space removal. There are two spaces between Int128
and s128 in ppc_vsr_t struct, where it should be only one.

Signed-off-by: Víctor Colombo <victor.colombo@eldorado.org.br>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20220906125523.38765-2-victor.colombo@eldorado.org.br>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>