x86: move FIX_EARLYCON_MEM kconfig into x86

In preparation to support FIX_EARLYCON_MEM on other arches, make the
option per arch.

Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/x86/Kconfig

@@ -261,6 +261,9 @@ config ARCH_HWEIGHT_CFLAGS
 config ARCH_SUPPORTS_UPROBES
 	def_bool y
 
+config FIX_EARLYCON_MEM
+	def_bool y
+
 source "init/Kconfig"
 source "kernel/Kconfig.freezer"
 

drivers/tty/serial/8250/Kconfig

@@ -90,11 +90,6 @@ config SERIAL_8250_CONSOLE
 
 	  If unsure, say N.
 
-config FIX_EARLYCON_MEM
-	bool
-	depends on X86
-	default y
-
 config SERIAL_8250_GSC
 	tristate
 	depends on SERIAL_8250 && GSC