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/tools/mkenvimage.c b/tools/mkenvimage.c
index a8eebab..b05f834 100644
--- a/tools/mkenvimage.c
+++ b/tools/mkenvimage.c
@@ -14,6 +14,7 @@
 #include <stdlib.h>
 #include <stdint.h>
 #include <string.h>
+#include <u-boot/crc.h>
 #include <unistd.h>
 #include <libgen.h>
 #include <sys/types.h>