runtime: correct misplaced right brace in Linux SIGBUS handling

I'm not sure how to write a test for this.  The change in
behaviour is that if you somehow get a SIGBUS signal for an
address >= 0x1000, the program will now crash rather than
calling panic.  As far as I know, on x86 GNU/Linux, the only
way to get a SIGBUS (rather than a SIGSEGV) is to set the
stack pointer to an invalid value.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/7906045

src/pkg/runtime/os_linux.c

@@ -225,8 +225,8 @@ runtime·sigpanic(void)
 		if(g->sigcode0 == BUS_ADRERR && g->sigcode1 < 0x1000) {
 			if(g->sigpc == 0)
 				runtime·panicstring("call of nil func value");
-			}
 			runtime·panicstring("invalid memory address or nil pointer dereference");
+		}
 		runtime·printf("unexpected fault address %p\n", g->sigcode1);
 		runtime·throw("fault");
 	case SIGSEGV: