Tune DTrace 'aframes' for the FBT and profile providers on arm64.

In both cases, too few frames were trimmed, leading to exception handling
or DTrace internals being exposed in stack traces exposed by D's stack()
primitive.

MFC after:	3 days
Reviewed by:	emaste, andrew

sys/cddl/dev/fbt/aarch64/fbt_isa.c

@@ -44,6 +44,7 @@
 #define	FBT_PATCHVAL		(AARCH64_BRK | AARCH64_BRK_IMM16_VAL)
 #define	FBT_ENTRY	"entry"
 #define	FBT_RETURN	"return"
+#define	FBT_AFRAMES	4
 
 int
 fbt_invop(uintptr_t addr, struct trapframe *frame, uintptr_t rval)
@@ -154,7 +155,7 @@ fbt_provide_module_function(linker_file_t lf, int symindx,
 	fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO);
 	fbt->fbtp_name = name;
 	fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
-	    name, FBT_ENTRY, 3, fbt);
+	    name, FBT_ENTRY, FBT_AFRAMES, fbt);
 	fbt->fbtp_patchpoint = instr;
 	fbt->fbtp_ctl = lf;
 	fbt->fbtp_loadcnt = lf->loadcnt;
@@ -196,7 +197,7 @@ fbt_provide_module_function(linker_file_t lf, int symindx,
 	fbt->fbtp_name = name;
 	if (retfbt == NULL) {
 		fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
-		    name, FBT_RETURN, 3, fbt);
+		    name, FBT_RETURN, FBT_AFRAMES, fbt);
 	} else {
 		retfbt->fbtp_probenext = fbt;
 		fbt->fbtp_id = retfbt->fbtp_id;

sys/cddl/dev/profile/profile.c

@@ -123,8 +123,7 @@ struct profile_probe_percpu;
 #endif
 
 #ifdef __aarch64__
-/* TODO: verify */
-#define	PROF_ARTIFICIAL_FRAMES	10
+#define	PROF_ARTIFICIAL_FRAMES	12
 #endif
 
 #ifdef __riscv