Tegra: delay_timer: fix MISRA defects
Tegra: delay_timer: fix MISRA defects

Main fixes:

* Include header file for function declarations [Rule 8.4]
* Move global object into function [Rule 8.9]

Change-Id: I1bc9f3f0ebd4ffc0b8444ac856cd97b0cb56bda4
Signed-off-by: Anthony Zhou <73aac1c215d5dc4b872f9dcd89236806f5a053ae@nvidia.com>

achingupta/arm-trusted-firmware,lsigithub/arm-trusted-firmware_public,lsigithub/arm-trusted-firmware_public,achingupta/arm-trusted-firmware