sw64: ftrace: restore the register storing direct call address

The register storing direct called trampoline's address is only saved,
but not restored. This commit fixes this issue.

Signed-off-by: Gu Yuchen <[email protected]>
Reviewed-by: He Sheng <[email protected]>
Signed-off-by: Gu Zitao <[email protected]>

Author: Gu Yuchen

arch/sw_64/kernel/entry-ftrace.S

@@ -341,6 +341,7 @@ ftrace_regs_call:
 	RESTORE_GRAPH_REG_ARGS
 	call    ftrace_graph_caller
 #endif
+	ldl     $2, PT_REGS_R2($sp)		// load direct call addr
 	RESTORE_PT_REGS
 	bne	$2, .Ldirect
 	ret	$31, ($28), 1