tracing: Simplify the Kconfig dependency of FTRACE

The entire FTRACE block is surrounded by 'if TRACING_SUPPORT' ...
'endif'.

Using 'depends on' is a simpler way to guard FTRACE.

Link: https://lkml.kernel.org/r/[e-mail]

Signed-off-by: Masahiro Yamada <[e-mail]>
Signed-off-by: Steven Rostedt (VMware) <[e-mail]>

kernel/trace/Kconfig

···
 	depends on STACKTRACE_SUPPORT
 	default y
 
-if TRACING_SUPPORT
-
 menuconfig FTRACE
 	bool "Tracers"
+	depends on TRACING_SUPPORT
 	default y if DEBUG_KERNEL
 	help
 	  Enable the kernel tracing infrastructure.
···
           If unsure, say N.
 
 endif # FTRACE
-
-endif # TRACING_SUPPORT
-