arm64: debug: remove noisy, pointless warning

Sending a SIGTRAP to a user task after execution of a BRK instruction at
EL0 is fundamental to the way in which software breakpoints work and
doesn't deserve a warning to be logged in dmesg. Whilst the warning can
be justified from EL1, do_debug_exception will already do the right thing,
so simply remove the code altogether.

Cc: Sandeepa Prabhu <sandeepa.prabhu@linaro.org>
Reported-by: Kyrylo Tkachov <kyrylo.tkachov@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
(cherry picked from commit 43683afbcb32f7b7318ac1badd6469d91fe22711)
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index 91a12d0..d202656 100644
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -320,9 +320,6 @@
 	if (call_break_hook(regs, esr) == DBG_HOOK_HANDLED)
 		return 0;
 
-	pr_warn("unexpected brk exception at %lx, esr=0x%x\n",
-			(long)instruction_pointer(regs), esr);
-
 	if (!user_mode(regs))
 		return -EFAULT;