crc32: Use the crc.h header for crc functions

Drop inclusion of crc.h in common.h and use the correct header directly
instead.

With this we can drop the conflicting definition in fw_env.h and rely on
the crc.h header, which is already included.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/mtd/ubispl/ubispl.c b/drivers/mtd/ubispl/ubispl.c
index 3f3b9b4..00102fc 100644
--- a/drivers/mtd/ubispl/ubispl.c
+++ b/drivers/mtd/ubispl/ubispl.c
@@ -9,6 +9,7 @@
 
 #include <common.h>
 #include <errno.h>
+#include <u-boot/crc.h>
 #include <ubispl.h>
 
 #include <linux/crc32.h>