net: move ether_crc to tsec driver

ether_crc was added to the core net code in commit 53a5c424bf86
("multicast tftp: RFC2090") so that other drivers could use it. However
the only current user of it is tsec.c so move it there.

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/drivers/net/tsec.c b/drivers/net/tsec.c
index 03a46da..9a4fab8 100644
--- a/drivers/net/tsec.c
+++ b/drivers/net/tsec.c
@@ -80,6 +80,31 @@
 
 #ifdef CONFIG_MCAST_TFTP
 
+/* the 'way' for ethernet-CRC-32. Spliced in from Linux lib/crc32.c
+ * and this is the ethernet-crc method needed for TSEC -- and perhaps
+ * some other adapter -- hash tables
+ */
+#define CRCPOLY_LE 0xedb88320
+static u32 ether_crc(size_t len, unsigned char const *p)
+{
+	int i;
+	u32 crc;
+
+	crc = ~0;
+	while (len--) {
+		crc ^= *p++;
+		for (i = 0; i < 8; i++)
+			crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY_LE : 0);
+	}
+	/* an reverse the bits, cuz of way they arrive -- last-first */
+	crc = (crc >> 16) | (crc << 16);
+	crc = (crc >> 8 & 0x00ff00ff) | (crc << 8 & 0xff00ff00);
+	crc = (crc >> 4 & 0x0f0f0f0f) | (crc << 4 & 0xf0f0f0f0);
+	crc = (crc >> 2 & 0x33333333) | (crc << 2 & 0xcccccccc);
+	crc = (crc >> 1 & 0x55555555) | (crc << 1 & 0xaaaaaaaa);
+	return crc;
+}
+
 /* CREDITS: linux gianfar driver, slightly adjusted... thanx. */
 
 /* Set the appropriate hash bit for the given addr */