Add hwspinlock support for the CSR atlas7 SoC.
The Hardware Spinlock device on atlas7 provides hardware assistance
for synchronization between the multiple processors in the system
(dual Cortex-A7, CAN bus Cortex-M3 and audio DSP).
Reviewed-by: Suman Anna
Reviewed-by: Bjorn Andersson
Signed-off-by: Wei Chen
Signed-off-by: Barry Song
Signed-off-by: Ohad Ben-Cohen