powerpc/book3s64: Move PPC_DT_CPU_FTRs and enable it by default

The PPC_DT_CPU_FTRs is a bit misplaced in menuconfig, it shows up with
other general kernel options. It's really more at home in the "Platform
Support" section, so move it there.

Also enable it by default, for Book3s 64. It does mostly nothing unless
the device tree properties are found, and we will want it enabled
eventually in distro kernels, so turn it on to start getting more
testing.

Fixes: 5a61ef74 ("powerpc/64s: Support new device tree binding for discovering CPU features")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/Kconfig

@@ -380,17 +380,6 @@ source "arch/powerpc/platforms/Kconfig"
 
 menu "Kernel options"
 
-config PPC_DT_CPU_FTRS
-	bool "Device-tree based CPU feature discovery & setup"
-	depends on PPC_BOOK3S_64
-	default n
-	help
-	  This enables code to use a new device tree binding for describing CPU
-	  compatibility and features. Saying Y here will attempt to use the new
-	  binding if the firmware provides it. Currently only the skiboot
-	  firmware provides this binding.
-	  If you're not sure say Y.
-
 config HIGHMEM
 	bool "High memory support"
 	depends on PPC32

arch/powerpc/platforms/Kconfig

@@ -59,6 +59,17 @@ config PPC_OF_BOOT_TRAMPOLINE
 
 	  In case of doubt, say Y
 
+config PPC_DT_CPU_FTRS
+	bool "Device-tree based CPU feature discovery & setup"
+	depends on PPC_BOOK3S_64
+	default y
+	help
+	  This enables code to use a new device tree binding for describing CPU
+	  compatibility and features. Saying Y here will attempt to use the new
+	  binding if the firmware provides it. Currently only the skiboot
+	  firmware provides this binding.
+	  If you're not sure say Y.
+
 config UDBG_RTAS_CONSOLE
 	bool "RTAS based debug console"
 	depends on PPC_RTAS