drivers: clock_control: clock_control_mcux_syscon: make clock IDs unique

Syscon clock driver previously used a sequence where clock IDs increased
sequentially. This had a few disadvantages:
- if a new SOC was introduced with more instances of a given IP, the
  clock ID could not be sequential with the remaining IDs
- chance of collisions between clock IDs was relatively high

To resolve this, define LPC clock IDs using a bitmask macro. Note that
the CTIMER clock IDs are used within SOC clock files to perform clock
init, and the macro requires that the clock ID expand to an integer
rather than a expression with bitshifts (hence why the macro is not used
for these IDs)

Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>