misc: Add the SE mode m5 ops to m5ops.h.

These shouldn't be called in fs mode through the m5 utility and
probably shouldn't be called directly either, but this makes them
consistent with the other functions which are mentioned in
asm/generic/m5ops.h.

Change-Id: I80df8b4d507350bc6d2763e770e38e0370931632
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/27236
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

include/gem5/m5ops.h

@@ -62,6 +62,9 @@ void m5_panic(void);
 void m5_work_begin(uint64_t workid, uint64_t threadid);
 void m5_work_end(uint64_t workid, uint64_t threadid);
 
+void m5_se_syscall();
+void m5_se_page_fault();
+
 #ifdef __cplusplus
 }
 #endif