Interface: Fix veneer function naming

Some veneer functions are named with "tfm_tfm_" prefix. It is confusing
and unfriendly to NS integration.

This patch unifies the prefix of all the veneer function as "tfm_"
- Fix the duplicated "tfm_" prefixes by checking secure function prefix
  in tfm_veneer template.
- Replace all the "tfm_tfm_" prefixes with "tfm_".

Change-Id: Id658486f49f4a6f1f22fd3897be27865889474ae
Signed-off-by: David Hu <david.hu@arm.com>
11 files changed