target/ppc: Rename sfprf to sfifprf where it's also used as set fi flag

The bit FI fix used the sfprf flag as a flag for the set_fi parameter
in do_float_check_status where applicable. Now, this patch rename this
flag to sfifprf to state this dual usage.

Signed-off-by: Víctor Colombo <victor.colombo@eldorado.org.br>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Rashmica Gupta <rashmica.g@gmail.com>
Message-Id: <20220517161522.36132-4-victor.colombo@eldorado.org.br>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>