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>

lib/Makefile

@@ -35,6 +35,7 @@ obj-$(CONFIG_CIRCBUF) += circbuf.o
 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