How to specify a hardware timer peripheral as the system clock device

I have placed an interval timer in to my design and want to use it as an alarm utilizing the HAL API functions for an alarm. My understanding is that before I can do that, I need to specify the timer to be the system clock device.

I see a reference to doing this by manipulating the BSP settings. I also found a reference to a "hal.sys_clk_timer" setting, but I am not sure how I go about changing this setting.

How do I change this setting and have the BSP updated with the change?