Staging: silicom: remove typedef for dev_desc_t

Remove the dev_desc_t typedef for the dev_desc struct in bpctl_mod.c,
resolving a checkpatch.pl warning. In fact, we can use an anonymous
struct, since it's only used in the single dev_desc array of device
descriptions, whose definition follows immediately.

Signed-off-by: Chad Williamson <chad@dahc.us>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>