bitops: introduce CONFIG_GENERIC_FIND_BIT_LE

This introduces CONFIG_GENERIC_FIND_BIT_LE to tell whether to use generic
implementation of find_*_bit_le() in lib/find_next_bit.c or not.

For now we select CONFIG_GENERIC_FIND_BIT_LE for all architectures which
enable CONFIG_GENERIC_FIND_NEXT_BIT.

But m68knommu wants to define own faster find_next_zero_bit_le() and
continues using generic find_next_{,zero_}bit().
(CONFIG_GENERIC_FIND_NEXT_BIT and !CONFIG_GENERIC_FIND_BIT_LE)

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Greg Ungerer <gerg@uclinux.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/find_next_bit.c b/lib/find_next_bit.c
index 7667c3d..b0a8767 100644
--- a/lib/find_next_bit.c
+++ b/lib/find_next_bit.c
@@ -160,6 +160,7 @@
 #endif /* CONFIG_GENERIC_FIND_FIRST_BIT */
 
 #ifdef __BIG_ENDIAN
+#ifdef CONFIG_GENERIC_FIND_BIT_LE
 
 /* include/linux/byteorder does not support "unsigned long" type */
 static inline unsigned long ext2_swabp(const unsigned long * x)
@@ -273,4 +274,6 @@
 	return result + __ffs(ext2_swab(tmp));
 }
 EXPORT_SYMBOL(find_next_bit_le);
+
+#endif /* CONFIG_GENERIC_FIND_BIT_LE */
 #endif /* __BIG_ENDIAN */