net: dm9051: Make remove() callback a void function

Changes introduced since the merge window in the spi subsystem and
available at:

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git tags/spi-remove-void

make the remove() callback for spi return void rather than int, breaking
the newly added dm9051 driver fail to build.  This patch fixes this
issue, converting the remove() function provided by the driver to return
void.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
[Rewrote commit message -- broonie]
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220228173957.1262628-2-broonie@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>