serial: fsl_linflexuart: don't call uart_write_wakeup() twice

linflex_txint() calls linflex_transmit_buffer() which calls
uart_write_wakeup(). So there is no point to repeat it in
linflex_txint() again -- remove it.

Cc: Stefan-gabriel Mirea <stefan-gabriel.mirea@nxp.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220124071430.14907-10-jslaby@suse.cz


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>