drivers: serial: uart_sam0: Correct check for interrupts enabled

Fixes the issue where uart_sam0_irq_tx_ready would return true if
the INTFLAG was set even though the INTSET bit for the given
interrupt was not enabled yet through uart_sam0_irq_tx_enable.

Signed-off-by: Ron Smith <rockyowl171@gmail.com>
1 file changed