docs: do not document CT_KERNEL_ARCH, it's going away...
Since we merged the 32/64-bit archs, and we explicitly used
the Linux kernel arch name, we can get rid of CT_KERNEL_ARCH.
1 # ia64 specific config options
2 # depends on EXPERIMENTAL
5 select ARCH_SUPPORTS_64
8 select ARCH_SUPPORTS_BOTH_ENDIAN
10 The ia64 architecture, as defined by:
11 http://www.intel.com/design/itanium/arch_spec.htm