py/mpconfig: Enable 2-argument built-in next() at basic feature level.

This is a pretty fundamental built-in and having CPython-compatible
behaviour is beneficial.  The code size increase is not much, and
ports/boards can still disable it if needed to save space.

Addresses issue micropython#5384.

Signed-off-by: Damien George <damien@micropython.org>

Author: dpgeorge

py/mpconfig.h

@@ -1215,7 +1215,7 @@ typedef double mp_float_t;
 
 // Support for calling next() with second argument
 #ifndef MICROPY_PY_BUILTINS_NEXT2
-#define MICROPY_PY_BUILTINS_NEXT2 (MICROPY_CONFIG_ROM_LEVEL_AT_LEAST_EVERYTHING)
+#define MICROPY_PY_BUILTINS_NEXT2 (MICROPY_CONFIG_ROM_LEVEL_AT_LEAST_BASIC_FEATURES)
 #endif
 
 // Whether to support rounding of integers (incl bignum); eg round(123,-1)=120