Tegra: gic: fix MISRA defects

Main fixes:

* Use int32_t replace int, use uint32_t replace unsign int [Rule 4.6]
* 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]
* Force operands of an operator to the same type category [Rule 10.4]
* Fixed assert/if statements conditions to be essentially boolean [Rule 14.4]
* Added curly braces ({}) around if statements in order to
  make them compound [Rule 15.6]
* Convert macros form headers to unsigned ints

Change-Id: I8051cc16499cece2039c9751bd347645f40f0901
Signed-off-by: Anthony Zhou <anzhou@nvidia.com>
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>