Commit 83a119160 fixed SMP by removing call to uart_xmitchars from inside spinlock.
This only works for SMP, since uart_xmitchars has a lock only in SMP. In a single
core configuration the function can be called in parallel from the interrupt
handler and from the imx9_txint.
Fix this by filling the uart buffers already before enabling the
interrupt, this way it is not possible to get the function called in parallel
for the same device.
Signed-off-by: Jukka Laitinen <jukka.laitinen@tii.ae>
5594c2e887