arm64: makefile: fix perf_callchain.o kconfig dependency

Commit 4b3dc967 ("arm64: force CONFIG_SMP=y and remove redundant
#ifdefs") incorrectly resolved a conflict on arch/arm64/kernel/Makefile
which resulted in a partial revert of 52da443e ("arm64: perf: factor
out callchain code"), leading to perf_callchain.o depending on
CONFIG_HW_PERF_EVENTS instead of CONFIG_PERF_EVENTS.

This patch restores the kconfig dependency for perf_callchain.o.
Reported-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/kernel/Makefile

@@ -25,8 +25,8 @@ arm64-obj-$(CONFIG_COMPAT)		+= sys32.o kuser32.o signal32.o 	\
 					   ../../arm/kernel/opcodes.o
 arm64-obj-$(CONFIG_FUNCTION_TRACER)	+= ftrace.o entry-ftrace.o
 arm64-obj-$(CONFIG_MODULES)		+= arm64ksyms.o module.o
-arm64-obj-$(CONFIG_PERF_EVENTS)		+= perf_regs.o
-arm64-obj-$(CONFIG_HW_PERF_EVENTS)	+= perf_event.o perf_callchain.o
+arm64-obj-$(CONFIG_PERF_EVENTS)		+= perf_regs.o perf_callchain.o
+arm64-obj-$(CONFIG_HW_PERF_EVENTS)	+= perf_event.o
 arm64-obj-$(CONFIG_HAVE_HW_BREAKPOINT)	+= hw_breakpoint.o
 arm64-obj-$(CONFIG_CPU_PM)		+= sleep.o suspend.o
 arm64-obj-$(CONFIG_CPU_IDLE)		+= cpuidle.o