spi: spi-topcliff-pch: Fix sparse warnings
spi: spi-topcliff-pch: Fix sparse warnings

Fixes the following type of warnings:
drivers/spi/spi-topcliff-pch.c:370:52: warning:
Using plain integer as NULL pointer

Signed-off-by: Sachin Kamat <1c3b1584a6008857f36c03c58f657c0fc16fc09e@linaro.org>
Signed-off-by: Mark Brown <b51b9a92386687a9ac927cebfa0f978adeb8cea5@linaro.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs