samd21: Enable terse error reporting on resource constrained chip family

This reclaims over 1kB of flash space by simplifying certain exception
messages.  e.g., it will no longer display the requested/actual length
when a fixed list/tuple of N items is needed:

        if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {
            mp_raise_ValueError(translate("tuple/list has wrong length"));
        } else {
            mp_raise_ValueError_varg(translate("requested length %d but object has length %d"),
                (int)len, (int)seq_len);

Other chip families including samd51 keep their current error reporting
capabilities.

Author: jepler

ports/atmel-samd/mpconfigport.h

@@ -42,6 +42,7 @@
 #define CIRCUITPY_MCU_FAMILY                        samd21
 #define MICROPY_PY_SYS_PLATFORM                     "Atmel SAMD21"
 #define SPI_FLASH_MAX_BAUDRATE 8000000
+#define MICROPY_ERROR_REPORTING (MICROPY_ERROR_REPORTING_TERSE)
 #define MICROPY_PY_BUILTINS_NOTIMPLEMENTED          (0)
 #define MICROPY_PY_FUNCTION_ATTRS                   (0)
 // MICROPY_PY_UJSON depends on MICROPY_PY_IO

py/circuitpy_mpconfig.h

@@ -64,7 +64,9 @@
 #define MICROPY_ENABLE_FINALISER         (1)
 #define MICROPY_ENABLE_GC                (1)
 #define MICROPY_ENABLE_SOURCE_LINE       (1)
+#ifndef MICROPY_ERROR_REPORTING
 #define MICROPY_ERROR_REPORTING          (MICROPY_ERROR_REPORTING_NORMAL)
+#endif
 #define MICROPY_FLOAT_HIGH_QUALITY_HASH  (0)
 #define MICROPY_FLOAT_IMPL               (MICROPY_FLOAT_IMPL_FLOAT)
 #define MICROPY_GC_ALLOC_THRESHOLD       (0)