drivers: dma_mcux_lpc: Replace sem with spinlock

Replace the otrig configuration semaphore with a spinlock.

This will allow the dma_config function to be called from an ISR
and it will no longer shift the burden of waiting to be able to configure
the dma otrigs to the caller of the function, since the driver
will just spin on the lock until it can configure them, instead of
returning an error.

Signed-off-by: Declan Snyder <declan.snyder@nxp.com>