microblaze: use the generic lib/checksum.c

The microblaze checksum code is mostly identical to
the asm-generic+lib version, so use that instead.

Signed-off-by: Remis Lima Baima <remis.developer@googlemail.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>
diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig
index b50b845..2db722d 100644
--- a/arch/microblaze/Kconfig
+++ b/arch/microblaze/Kconfig
@@ -53,6 +53,9 @@
 config GENERIC_GPIO
 	def_bool y
 
+config GENERIC_CSUM
+	def_bool y
+
 config PCI
 	def_bool n