util_libs: remove autoconf.h from util_libs

this commit removes autoconf.h generation from each lib and
append '#include <<lib_name>/gen_config.h>' after each
'#include <autoconf.h>' since autoconf.h is only the for the
kernel config now. This is a temporarily solution, since we
currently don't have a way to tell which header files each file
is trying to include when it includes 'autoconf.h'

platsupport: extend generic timer implementation

- update generic timer implementation to work on aarch64 in addition to
aarch32.
- add more manipulation functions for using the generic timer when it is
exported to user level.

Note that exporting the generic timer to user level exposes a timing
channel. This should only be done for testing and benchmarking and never
in a verified configuration of the kernel.

platsupport: move comment to header

This comment belongs in the public interface, not the source.

platsupport: for arm, always compile generic_timer

Compile generic_timer.c even if CONFIG_EXPORT_PCNT_USER is not set.
Instead, return an error if the initialisation function is called. This
means we always compile the code which eases maintenance.

Remove pstimer_t from generic timer

fix licenses