Add FVP system peripheral driver

The system peripheral on the FVP manages several system-level features,
including:
* System and processor identification
* LED and switch control
* Handling of volatile and non-volatile flags
* 100Hz and 24MHz counters
* System operations such as shutdown and reboot
* Various other miscellaneous functions

Signed-off-by: Imre Kis <imre.kis@arm.com>
Change-Id: I6f18ec55d9baf6b217d95ee01b96cd31ecfb0bbd
2 files changed