crc16: Move standard CRC-16 implementation from ubifs to lib

This implementation provides standard CRC-16 algorithm with polynomial
x^16 + x^15 + x^2 + 1.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/lib/Makefile b/lib/Makefile
index cf662a7..d9b1811 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -35,6 +35,7 @@
 endif
 
 obj-y += crc8.o
+obj-y += crc16.o
 obj-y += crc16-ccitt.o
 obj-$(CONFIG_ERRNO_STR) += errno_str.o
 obj-$(CONFIG_FIT) += fdtdec_common.o