spi: tegra114: Remove unnecessary NULL-pointer checks

cs_setup, cs_hold and cs_inactive points to fields of spi_device struct,
so there is no sense in checking them for NULL.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 04e6bb0d ("spi: modify set_cs_timing parameter")
Signed-off-by: Alexander Danilenko <al.b.danilenko@gmail.com>
Link: https://lore.kernel.org/r/20230815092058.4083-1-al.b.danilenko@gmail.com


Signed-off-by: Mark Brown <broonie@kernel.org>