kernel/linux: Cleanup unneeded files from 'headers_check' and 'headers_install'

headers_install makes .install and ..install.cmd files.
headers_check makes .check and ..check.cmd files.
Remove these files uncoditionaly after installing (and checking) header files
into the sys-root.

Signed-off-by: Bryan Hundven <bryanhundven@gmail.com>
[Yann E. MORIN: reformat the patch, move hunk out of headers_check conditional]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

source "config/backend.in"

source "config/global.in"

source "config/target.in"

source "config/toolchain.in"

source "config/kernel.in"

source "config/binutils.in"

source "config/cc.in"

source "config/libc.in"

source "config/debug.in"

source "config/companion_libs.in"

source "config/companion_tools.in"

source "config/test_suite.in"