binfmt_flat: add a ARCH_HAS_BINFMT_FLAT option

Allow architectures to opt into ARCH_HAS_BINFMT_FLAT support instead of
assuming that all nommu ports support the format.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
diff --git a/arch/h8300/Kconfig b/arch/h8300/Kconfig
index 7457f19..ec800e9 100644
--- a/arch/h8300/Kconfig
+++ b/arch/h8300/Kconfig
@@ -2,6 +2,7 @@
 config H8300
         def_bool y
 	select ARCH_32BIT_OFF_T
+	select ARCH_HAS_BINFMT_FLAT
 	select BINFMT_FLAT_ARGVP_ENVP_ON_STACK
 	select BINFMT_FLAT_OLD_ALWAYS_RAM
 	select GENERIC_ATOMIC64