samples: add HAVE_SAMPLE_FTRACE_DIRECT config option

Add HAVE_SAMPLE_FTRACE_DIRECT config option which can be selected by
architectures which have support for ftrace direct call samples.
Acked-by: NIlya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: NSven Schnelle <svens@linux.ibm.com>
Signed-off-by: NHeiko Carstens <hca@linux.ibm.com>
Acked-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20211012133802.2460757-4-hca@linux.ibm.comSigned-off-by: NVasily Gorbik <gor@linux.ibm.com>

arch/x86/Kconfig

@@ -190,6 +190,7 @@ config X86
 	select HAVE_DYNAMIC_FTRACE_WITH_REGS
 	select HAVE_DYNAMIC_FTRACE_WITH_ARGS	if X86_64
 	select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+	select HAVE_SAMPLE_FTRACE_DIRECT	if X86_64
 	select HAVE_EBPF_JIT
 	select HAVE_EFFICIENT_UNALIGNED_ACCESS
 	select HAVE_EISA

samples/Kconfig

@@ -26,7 +26,7 @@ config SAMPLE_TRACE_PRINTK
 config SAMPLE_FTRACE_DIRECT
 	tristate "Build register_ftrace_direct() example"
 	depends on DYNAMIC_FTRACE_WITH_DIRECT_CALLS && m
-	depends on X86_64 # has x86_64 inlined asm
+	depends on HAVE_SAMPLE_FTRACE_DIRECT
 	help
 	  This builds an ftrace direct function example
 	  that hooks to wake_up_process and prints the parameters.
@@ -224,3 +224,6 @@ config SAMPLE_WATCH_QUEUE
 	  sb_notify() syscalls and the KEYCTL_WATCH_KEY keyctl() function.
 
 endif # SAMPLES
+
+config HAVE_SAMPLE_FTRACE_DIRECT
+	bool