ASoC: davinci-evm: drop un-necessary remove function

As davinci card gets registered using 'devm_' api
there is no need to unregister the card in 'remove'
function.
Hence drop the 'remove' function.

Fixes: ee2f615d (ASoC: davinci-evm: Add device tree binding)
Signed-off-by: Manish Badarkhe <manishvb@ti.com>
Signed-off-by: Jyri Sarha <jsarha@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org