components/linux_drivers: Add misc driver for PFDI

Introduce a new misc driver enabling secure communication between
userspace (EL0) and the PFDI runner (EL3) via ARM SMC calls. The
driver supports

 - Querying the PFDI version and supported features.
 - Retrieving PE test IDs and initiating test runs with specified
   test bounds.
 - Obtaining test results and performing firmware checks.
 - Forcing error conditions through controlled SMC invocations.

It uses per-CPU devices with proper locking to ensure safe operations.

Signed-off-by: Divin Raj <divin.raj@arm.com>