target/ppc: Remove msr_cm macro

msr_cm 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: <20220504210541.115256-14-victor.colombo@eldorado.org.br>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
diff --git a/target/ppc/mmu_helper.c b/target/ppc/mmu_helper.c
index 5bb5c71..15239dc 100644
--- a/target/ppc/mmu_helper.c
+++ b/target/ppc/mmu_helper.c
@@ -1003,7 +1003,7 @@
     /* Add a mask for page attributes */
     mask |= MAS2_ACM | MAS2_VLE | MAS2_W | MAS2_I | MAS2_M | MAS2_G | MAS2_E;
 
-    if (!msr_cm) {
+    if (!FIELD_EX64(env->msr, MSR, CM)) {
         /*
          * Executing a tlbwe instruction in 32-bit mode will set bits
          * 0:31 of the TLB EPN field to zero.