kernel/linux: deprecate copying headers from pre-instaleld headers

No-one ever inquired about this feature. Due to the way it works, it is
rather unlikely that every user used a properly-formatted tarball, or a
properly structured directory as imput.

Beside, it is not really easy to maintain: I just spent one full day
remembering how it worked... Sigh... :-(

Just deprecate this, until next release, or until someone complains.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

# x86 specific options

## select ARCH_SUPPORTS_32

## select ARCH_SUPPORTS_64

## select ARCH_DEFAULT_32

## select ARCH_USE_MMU

## select ARCH_SUPPORT_ARCH

## select ARCH_SUPPORT_CPU

## select ARCH_SUPPORT_TUNE

##

## help The x86 architecture, as defined by:

## help     32-bit (ia32) : http://www.intel.com/

## help     64-bit (amd64): http://www.amd.com/us-en/Processors/DevelopWithAMD/0,,30_2252_875_7044,00.html