() Moves the architecture specific timing measurement APIs
under the timing measurement APIs group.
() Add SoC and board specific API groups.
() Document each SoC and board specific API so the doc shows up
for them.
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
Move this section under the kernel and alongside other core and low
level features that are tied to the kernel.
Signed-off-by: Anas Nashif <anas.nashif@intel.com>