Btrfs: use btrfs_crc32c everywhere instead of libcrc32c

After the commit titled "Btrfs: fix btrfs boot when compiled as built-in",
LIBCRC32C requirement was removed from btrfs' Kconfig. This made it not
possible to build a kernel with btrfs enabled (either as module or built-in)
if libcrc32c is not enabled as well. So just replace all uses of libcrc32c
with the equivalent function in btrfs hash.h - btrfs_crc32c.

Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 730dce3..cf9107a 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -24,12 +24,12 @@
 #include <linux/xattr.h>
 #include <linux/posix_acl_xattr.h>
 #include <linux/radix-tree.h>
-#include <linux/crc32c.h>
 #include <linux/vmalloc.h>
 #include <linux/string.h>
 
 #include "send.h"
 #include "backref.h"
+#include "hash.h"
 #include "locking.h"
 #include "disk-io.h"
 #include "btrfs_inode.h"
@@ -620,7 +620,7 @@
 	hdr->len = cpu_to_le32(sctx->send_size - sizeof(*hdr));
 	hdr->crc = 0;
 
-	crc = crc32c(0, (unsigned char *)sctx->send_buf, sctx->send_size);
+	crc = btrfs_crc32c(0, (unsigned char *)sctx->send_buf, sctx->send_size);
 	hdr->crc = cpu_to_le32(crc);
 
 	ret = write_buf(sctx->send_filp, sctx->send_buf, sctx->send_size,