math-emu: Fix thinko in _FP_DIV

In commit 48d6c64311 ("math-emu: Add
support for reporting exact invalid exception") code was added to
set the new FP_EX_INVALID_{IDI,ZDZ} exception flag bits.

However there is a missing break statement for the
_FP_CLS_COMBINE(FP_CLS_INF,FP_CLS_INF) switch case, the
code just falls into _FP_CLS_COMBINE(FP_CLS_ZERO,FP_CLS_ZERO)
which then proceeds to overwrite all of the settings.

Fix by adding the missing break.

Signed-off-by: David S. Miller <davem@davemloft.net>

include/math-emu/op-common.h

@@ -503,6 +503,8 @@ do {							\
     R##_c = FP_CLS_NAN;					\
     _FP_FRAC_SET_##wc(R, _FP_NANFRAC_##fs);		\
     FP_SET_EXCEPTION(FP_EX_INVALID | FP_EX_INVALID_IDI);\
+    break;						\
+							\
   case _FP_CLS_COMBINE(FP_CLS_ZERO,FP_CLS_ZERO):	\
     R##_s = _FP_NANSIGN_##fs;				\
     R##_c = FP_CLS_NAN;					\