target/cris: Mark helper_raise_exception noreturn

Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Tested-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

target/cris/helper.h

-DEF_HELPER_2(raise_exception, void, env, i32)
+DEF_HELPER_2(raise_exception, noreturn, env, i32)
 DEF_HELPER_2(tlb_flush_pid, void, env, i32)
 DEF_HELPER_2(spc_write, void, env, i32)
 DEF_HELPER_1(rfe, void, env)