ARM: mach-nuc93x: delete

This architecture received only generic maintenance since December 2009
when it was originally submitted, and no actual additional support since
then.  It has no defconfig entry either, meaning that it was never built
by the ARM KAutobuild.  Incidentally it currently doesn't build either
when CONFIG_MACH_NUC932EVB is selected which is the only possible config
choice.

This is therefore dead code and should be removed.  If someone wants to
revive this code, it could be retrieved from the Git repository, and
ideally be merged in mach-w90x900/ instead.

Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>