ARM: OMAP2+: Use ARM SMC Calling Convention when OP-TEE is available

On High-Security(HS) OMAP2+ class devices a couple actions must be
performed from the ARM TrustZone during boot. These traditionally can be
performed by calling into the secure ROM code resident in this secure
world using legacy SMC calls. Optionally OP-TEE can replace this secure
world functionality by replacing the ROM after boot. ARM recommends a
standard calling convention is used for this interaction (SMC Calling
Convention). We check for the presence of OP-TEE and use this type of
call to perform the needed actions, falling back to the legacy OMAP ROM
call if OP-TEE is not available.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>