media: cxd2880-spi: fix two memory leaks of dvb_spi

There are two return paths that do not kfree dvb_spi. Fix the memory
leaks by returning via the exit label fail_adapter that will free
dvi_spi.

Detected by CoverityScan, CID#1475991 ("Resource Leak")

Fixes: cb496cd4 ("media: cxd2880-spi: Add optional vcc regulator")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Yasunari Takiguchi <Yasunari.Takiguchi@sony.com&gt;?>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>