unified: rename sched.h to ksched.h

Build breaks when enabling CONFIG_NEWLIB_LIBC because it has its own
sched.h file.

This is a bad symptom of a greater issue: the build system passes many
'-I<path>' options to the compiler, and that allows including header
files by simply specifying their names (when located somewhere else than
<zephyr>/include/) and can cause clashes when several files in different
locations have the same name, like in this case.

Fixes ZEP-1062.

Change-Id: I81d1d69ee6669a609cd0c420b1b8f870d17dcb67
Signed-off-by: Benjamin Walsh <benjamin.walsh@windriver.com>
15 files changed