Fixed common_hal_busio_uart_deinited incorrect pin assignment check.

The pin must be tested instead of pin->number in the same way as in STM
I2C busio layer.

Author: EmergReanimator

ports/stm/common-hal/busio/SPI.c

@@ -250,7 +250,7 @@ void common_hal_busio_spi_never_reset(busio_spi_obj_t *self) {
 }
 
 bool common_hal_busio_spi_deinited(busio_spi_obj_t *self) {
-    return self->sck->pin == NULL;
+    return self->sck == NULL;
 }
 
 void common_hal_busio_spi_deinit(busio_spi_obj_t *self) {

ports/stm/common-hal/busio/UART.c

@@ -259,7 +259,7 @@ void common_hal_busio_uart_never_reset(busio_uart_obj_t *self) {
 }
 
 bool common_hal_busio_uart_deinited(busio_uart_obj_t *self) {
-    return self->tx->pin == NULL && self->rx->pin == NULL;
+    return self->tx == NULL && self->rx == NULL;
 }
 
 void common_hal_busio_uart_deinit(busio_uart_obj_t *self) {