Clear any pending exceptions before using frstor (in the non-FXSR case)

in npxsetregs() too.  npxsetregs() must overwrite the previous state, and
it is never paired with an npxgetregs() that would defuse the previous
state (since npxgetregs() would have fninit'ed the state, leaving nothing
to do).

PR:		68058 (this should complete the fix)
Tested by:	Simon Barner <barner@in.tum.de>

sys/i386/isa/npx.c

@@ -944,6 +944,10 @@ npxsetregs(td, addr)
 
 	s = intr_disable();
 	if (td == PCPU_GET(fpcurthread)) {
+#ifdef CPU_ENABLE_SSE
+		if (!cpu_fxsr)
+#endif
+			fnclex();	/* As in npxdrop(). */
 		fpurstor(addr);
 		intr_restore(s);
 	} else {