save about 112 bytes

[dhalbert]

Saves about 112 bytes on non-Express M0 builds:

• Remove MpyError exception, which wasn't used anywhere by us (EDIT: At one time it was used to display a RGB LED status color to indicate incompatible .mpy files. However, that was removed when the RGB status indicators were simplified.)
• Remove two redundant calls to reset_pin_number() in atmel-samd I2C. These calls are done in the deinit code, and don't need to be done before deinit is called.
• Change a few mp_printf() calls to mp_cprintf() with a translated string. I tried this in a number of places, and the only significant difference was the on in main.c. Very surprisingly, this change in run_boot_py() saves about 60 bytes:

        mp_printf(&mp_plat_print, "%s\nBoard ID:%s\n", MICROPY_FULL_VERSION_INFO, CIRCUITPY_BOARD_ID);
        #if CIRCUITPY_MICROCONTROLLER && COMMON_HAL_MCU_PROCESSOR_UID_LENGTH > 0
        uint8_t raw_id[COMMON_HAL_MCU_PROCESSOR_UID_LENGTH];
        common_hal_mcu_processor_get_uid(raw_id);
        mp_cprintf(&mp_plat_print, translate("UID:"));
        for (size_t i = 0; i < COMMON_HAL_MCU_PROCESSOR_UID_LENGTH; i++) {
            mp_cprintf(&mp_plat_print, translate("%02X"), raw_id[i]);
        }
        mp_printf(&mp_plat_print, "\n");

Both "UID:" and "%02X" must be translated to get the savings. If either one is omitted, the savings is much less. I looked at the assembly output, and it might be doing a better job of optimization, but I'm not sure why. Or something in the translation table construction reaches some inflection point. It's very odd. Neither string will need to actually be translated by the translators.

This will allow most but not all boards that are failing in #6923 to fit.

[jepler]

Looks good!