Do not use the e300 core decrementer auto-reload feature. We have to
use the normal decrementer handler since otherwise it is impossible to
pass test sptests/spnsext01.
The clock driver used previously the bsp_clicks_per_usec value. For a
33333333Hz time base frequency this leads to a relative error of one per
cent for example due to integer truncation.
* shared/clock/clock.c: The Shared Memory Driver no longer requires the
special IOCTL in Clock_control. This was a hack which has existed
since before the Classic API Timer Manager was implemented. All
implementations of and references to Clock_control were removed.
directly. Supports special variants for Book E and e300 cores. For
standard decrementer CPUs the new decrementer value is calculated with
reference to a time base so that a time drift is avoided
