riscv: add binfmt_flat support

Just use the generic definitions.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NGreg Ungerer <gerg@linux-m68k.org>

arch/riscv/Kconfig

@@ -17,6 +17,7 @@ config RISCV
 	select OF
 	select OF_EARLY_FLATTREE
 	select OF_IRQ
+	select ARCH_HAS_BINFMT_FLAT
 	select ARCH_WANT_FRAME_POINTERS
 	select CLONE_BACKWARDS
 	select COMMON_CLK

arch/riscv/include/asm/Kbuild

@@ -5,6 +5,7 @@ generic-y += compat.h
 generic-y += device.h
 generic-y += div64.h
 generic-y += extable.h
+generic-y += flat.h
 generic-y += dma.h
 generic-y += dma-contiguous.h
 generic-y += dma-mapping.h