commit 12cb89e3 upstream.

num-cs is 32 bit property, don't read just upper 16 bits.

Fixes: 4a8573ab (spi: qup: Remove chip select function)
Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>