drivers: pit: fix compiler warning when clocks disabled

[manuargue]

Prerequisites

• [x] I have checked latest main branch and the issue still exists.
• [x] I did not see it is stated as known-issue in release notes.
• [x] No similar GitHub issue is related to this change.
• [x] My code follows the commit guidelines of this project.
• [x] I have performed a self-review of my own code.
• [x] My changes generate no new warnings.
• [ ] I have added tests that prove my fix is effective or that my feature works.

Describe the pull request Add missing guards to avoid compilation warnings when building PIT driver with clock control driver disabled. Example of warning without this patch:

[136/182] Building C object modules/hal_nxp/hal_nxp/CM...__hal__nxp.dir/mcux/mcux-sdk/drivers/pit/fsl_pit.c.ob 
C:/Users/user/zephyr/modules/hal/nxp/mcux/mcux-sdk/drivers/pit/fsl_pit.c:42:17: warning: 'PIT_GetInstance' defined but not used [-Wunused-function]
   42 | static uint32_t PIT_GetInstance(PIT_Type *base)
      |

Type of change

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

Tests

• Test configuration (please complete the following information):
  • Hardware setting:
  • Toolchain: Zephyr SDK
  • Test Tool preparation:
  • Any other dependencies:
• Test executed Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce.
  • [x] Build Test
  • [x] Run Test

[manuargue]

Hi @mcuxsusan, FYI, I found this issue when integrating PIT driver for a Zephyr board. Not a blocking issue but an annoyance. We can patch it in Zephyr's HAL NXP side in the meantime.