signal/sparc: Move EMT_TAGOVF into the generic siginfo.h

When moving all of the architectures specific si_codes into
siginfo.h, I apparently overlooked EMT_TAGOVF.  Move it now.

Remove the now redundant test in siginfo_layout for SIGEMT
as now NSIGEMT is always defined.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

arch/sparc/include/uapi/asm/siginfo.h

@@ -17,10 +17,4 @@
 
 #define SI_NOINFO	32767		/* no information in siginfo_t */
 
-/*
- * SIGEMT si_codes
- */
-#define EMT_TAGOVF	1	/* tag overflow */
-#define NSIGEMT		1
-
 #endif /* _UAPI__SPARC_SIGINFO_H */