Fix FASTTRAPIOC_GETINSTR.

This ioctl is used when a breakpoint is encountered while disassembling
a symbol in the target process.  Since only one DTrace consumer can
toggle or enumerate fasttrap probes from a given process at time, this
ioctl does not appear to be used in practice.

sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c

@@ -2326,10 +2326,8 @@ err:
 		int ret;
 #endif
 
-#ifdef illumos
 		if (copyin((void *)arg, &instr, sizeof (instr)) != 0)
 			return (EFAULT);
-#endif
 
 #ifdef notyet
 		if (!PRIV_POLICY_CHOICE(cr, PRIV_ALL, B_FALSE)) {

sys/cddl/contrib/opensolaris/uts/common/sys/fasttrap.h

@@ -42,7 +42,7 @@ extern "C" {
 #define	FASTTRAPIOC_MAKEPROBE	(FASTTRAPIOC | 1)
 #define	FASTTRAPIOC_GETINSTR	(FASTTRAPIOC | 2)
 #else
-#define	FASTTRAPIOC_GETINSTR	_IOWR('f', 2, uint8_t)
+#define	FASTTRAPIOC_GETINSTR	_IO('f', 2)
 #define	FASTTRAPIOC_MAKEPROBE	_IO('f', 3)
 #endif