Rename crc functions to private namespace

Apparently we overlap with some gtk (?) crc32() functions, causing
ours to be called and subsequently crashing since the arguments
aren't the same.

Move everything to a fio_ protected namespace.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/crc/sha512.c b/crc/sha512.c
index 9268a49..e069a44 100644
--- a/crc/sha512.c
+++ b/crc/sha512.c
@@ -146,7 +146,7 @@
 	a = b = c = d = e = f = g = h = t1 = t2 = 0;
 }
 
-void sha512_init(struct sha512_ctx *sctx)
+void fio_sha512_init(struct fio_sha512_ctx *sctx)
 {
 	sctx->state[0] = H0;
 	sctx->state[1] = H1;
@@ -159,8 +159,8 @@
 	sctx->count[0] = sctx->count[1] = sctx->count[2] = sctx->count[3] = 0;
 }
 
-void sha512_update(struct sha512_ctx *sctx, const uint8_t *data,
-		   unsigned int len)
+void fio_sha512_update(struct fio_sha512_ctx *sctx, const uint8_t *data,
+		       unsigned int len)
 {
 	unsigned int i, idx, part_len;