Revert "ARM: dts: nomadik: Fix polarity of SPI CS"

This reverts commit fa946356.

Per Linus Walleij:

Dear ARM SoC maintainers,

can you please revert this patch. It was the wrong solution to the
wrong problem, and I must have acted in stress. Andrey fixed the
real bug in a proper way in these commits:

commit e5545c94
"gpio: of: Check propname before applying "cs-gpios" quirks"
commit 7ce40277
"gpio: of: Check for "spi-cs-high" in child instead of parent node"

Signed-off-by: Olof Johansson <olof@lixom.net>