linux-imx

tty: serial: lpuart: enable wakeup source for lpuart

When use lpuart with DMA mode as wake up source, it still switch to
cpu mode in .suspend() that enable cpu interrupts RIE and ILIE as
wakeup source. Enable the wakeup irq bits in .suspend_noirq() and
disable the wakeup irq bits in .resume_noirq().

For DMA mode, after system resume back, it needs to setup DMA again,
if DMA setup is failed, it switchs to CPU mode. .resume() will share
the HW setup code with .startup(), so abstract the same code to the
api like lpuartx_hw_setup().

Signed-off-by: Fugang Duan <fugang.duan@nxp.com>