sunhme: Use vdbg for spam-y prints

The SXD, TXD, and RXD macros are used only once (or twice). Just use the
vdbg print, which seems to have been devised for these sorts of very
verbose messages.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>