powerpc/64: Make COMPAT user-selectable disabled on littleendian by default.

On bigendian ppc64 it is common to have 32bit legacy binaries but much
less so on littleendian.

Signed-off-by: Michal Suchanek <[email protected]>
Reviewed-by: Christophe Leroy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/41393d6e895b0d3a47ee62f8f51e1cf888ad6226.1584699455.git.msuchanek@suse.de

Author: hramrach

arch/powerpc/Kconfig

@@ -264,8 +264,9 @@ config PANIC_TIMEOUT
 	default 180
 
 config COMPAT
-	bool
-	default y if PPC64
+	bool "Enable support for 32bit binaries"
+	depends on PPC64
+	default y if !CPU_LITTLE_ENDIAN
 	select COMPAT_BINFMT_ELF
 	select ARCH_WANT_OLD_COMPAT_IPC
 	select COMPAT_OLD_SIGACTION