target/ppc: Remove msr_ep macro

target/ppc: Remove msr_ep macro

msr_ep macro hides the usage of env->msr, which is a bad behavior
Substitute it with FIELD_EX64 calls that explicitly use env->msr
as a parameter.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Víctor Colombo <victor.colombo@eldorado.org.br>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220504210541.115256-17-victor.colombo@eldorado.org.br>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>