arm64: ftrace: fix ftrace_modify_graph_caller for branch replace

ftrace_enable_ftrace_graph_caller and ftrace_disable_ftrace_graph_caller
should replace B(jmp) instruction and not BL(call) instruction.

Commit 9f1ae759("arm64: Correct ftrace calls to
aarch64_insn_gen_branch_imm()") had a typo and used
AARCH64_INSN_BRANCH_LINK instead of AARCH64_INSN_BRANCH_NOLINK.

Either instruction will work, as the link register is saved/restored
across the branch but this better matches the intention of the code.
Signed-off-by: NPratyush Anand <panand@redhat.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

arch/arm64/kernel/ftrace.c

@@ -156,7 +156,7 @@ static int ftrace_modify_graph_caller(bool enable)
 
 	branch = aarch64_insn_gen_branch_imm(pc,
 					     (unsigned long)ftrace_graph_caller,
-					     AARCH64_INSN_BRANCH_LINK);
+					     AARCH64_INSN_BRANCH_NOLINK);
 	nop = aarch64_insn_gen_nop();
 
 	if (enable)