sys/cddl/compat: Redudant define in vfs.h

Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
sys/cddl: Rename curcpu -> mycpuid

Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
sys/cddl/compat: Remove conflicting opensolaris_utsname type

struct utsname is already defined in 'sys/sys/utsname.h'.

Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>