powerpc/ftrace: Fix confusing help text for DISABLE_MPROFILE_KERNEL

The final paragraph of the help text is reversed. We want to enable
this option by default, and disable it if the toolchain has a working
-mprofile-kernel.

Fixes: 8c50b72a3b4f ("powerpc/ftrace: Add Kconfig & Make glue for mprofile-kernel")
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/Kconfig

@@ -394,8 +394,8 @@ config DISABLE_MPROFILE_KERNEL
 	  be disabled also.
 
 	  If you have a toolchain which supports mprofile-kernel, then you can
-	  enable this. Otherwise leave it disabled. If you're not sure, say
-	  "N".
+	  disable this. Otherwise leave it enabled. If you're not sure, say
+	  "Y".
 
 config MPROFILE_KERNEL
 	depends on PPC64 && CPU_LITTLE_ENDIAN