sys>boot>geli build warnings

In file included from /usr/home/aprieger/repos/freebsd_master/freebsd/sys/boot/geli/geliboot_crypto.c:34:
/usr/home/aprieger/repos/freebsd_master/freebsd/sys/boot/geli/geliboot_internal.h:54:9: warning:
      '_STAND' macro redefined [-Wmacro-redefined]
#define _STAND
        ^
<command line>:3:9: note: previous definition is here
#define _STAND 1
        ^
/usr/home/aprieger/repos/freebsd_master/freebsd/sys/boot/geli/geliboot_crypto.c:85:28: warning:
      incompatible pointer types passing 'struct aes_xts_ctx *' to parameter of
      type 'caddr_t' (aka 'char *') [-Wincompatible-pointer-types]
                enc_xform_aes_xts.reinit(ctxp, iv);
                                         ^~~~
/usr/home/aprieger/repos/freebsd_master/freebsd/sys/boot/geli/geliboot_crypto.c:90:31: warning:
      incompatible pointer types passing 'struct aes_xts_ctx *' to parameter of
      type 'caddr_t' (aka 'char *') [-Wincompatible-pointer-types]
                                enc_xform_aes_xts.decrypt(ctxp, data + i);
                                                          ^~~~
/usr/home/aprieger/repos/freebsd_master/freebsd/sys/boot/geli/geliboot_crypto.c:95:31: warning:
      incompatible pointer types passing 'struct aes_xts_ctx *' to parameter of
      type 'caddr_t' (aka 'char *') [-Wincompatible-pointer-types]
                                enc_xform_aes_xts.encrypt(ctxp, data + i);
                                                          ^~~~
4 warnings generated.