samd/main: Fix sercom deinit ordering in soft-reset.

If sockets were open when calling soft reset, gc_sweep_all() would try to
close them.  In case of e.g. the NINA WiFi handler, connected through SPI,
spi_transfer() would be called for command exchange with the NINA module.
But at that time SerCom was already disabled.

Moving sercom_deinit_all() behind gc_sweep_all() solves this issue.

Signed-off-by: robert-hh <robert@hammelrath.com>

ports/samd/main.c

@@ -84,9 +84,9 @@ void samd_main(void) {
         adc_deinit_all();
         pin_irq_deinit_all();
         pwm_deinit_all();
-        sercom_deinit_all();
         soft_timer_deinit();
         gc_sweep_all();
+        sercom_deinit_all();
         mp_deinit();
     }
 }