This patch adds support for simulation platforms as well as
fixes issues flagged by the MISRA scans.

Main MISRA fixes:

* Added explicit casts (e.g. 0U) to integers in order for them to be
  compatible with whatever operation they're used in [Rule 10.1]
* Fix return type doesn't match the function type [Rule 10.3]
* Use single return point instead of multiple [Rule 15.5]
* Change return type for the tegra_platform_is_x handlers to bool

Change-Id: I871b7c37b22942f6c0c2049c14cc626d4a24d81c
Signed-off-by: Anthony Zhou <anzhou@nvidia.com>
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>