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/check-integrity.c b/fs/btrfs/check-integrity.c
index 160fb50..39bfd56 100644
--- a/fs/btrfs/check-integrity.c
+++ b/fs/btrfs/check-integrity.c
@@ -92,11 +92,11 @@
 #include <linux/slab.h>
 #include <linux/buffer_head.h>
 #include <linux/mutex.h>
-#include <linux/crc32c.h>
 #include <linux/genhd.h>
 #include <linux/blkdev.h>
 #include "ctree.h"
 #include "disk-io.h"
+#include "hash.h"
 #include "transaction.h"
 #include "extent_io.h"
 #include "volumes.h"
@@ -1823,7 +1823,7 @@
 		size_t sublen = i ? PAGE_CACHE_SIZE :
 				    (PAGE_CACHE_SIZE - BTRFS_CSUM_SIZE);
 
-		crc = crc32c(crc, data, sublen);
+		crc = btrfs_crc32c(crc, data, sublen);
 	}
 	btrfs_csum_final(crc, csum);
 	if (memcmp(csum, h->csum, state->csum_size))