target-ppc: update comment about precise emulation

Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6058 c046a42c-6fe2-441c-8c8c-71466251a162

target-ppc/exec.h

@@ -27,8 +27,7 @@
 #include "cpu.h"
 #include "exec-all.h"
 
-/* For normal operations, precise emulation should not be needed */
-//#define USE_PRECISE_EMULATION 1
+/* Precise emulation is need to correctly emulation exception flags */
 #define USE_PRECISE_EMULATION 1
 
 register struct CPUPPCState *env asm(AREG0);