将MICROPY_FLOAT_IMPL_DOUBLE改为FLOAT

使用32位浮点可以利用FPU进行加速

port/mpconfigport.h

@@ -115,7 +115,7 @@
 #define MICROPY_MODULE_FROZEN_STR   (0)
 #define MICROPY_CPYTHON_COMPAT      (1)
 #define MICROPY_LONGINT_IMPL        (MICROPY_LONGINT_IMPL_MPZ)
-#define MICROPY_FLOAT_IMPL          (MICROPY_FLOAT_IMPL_DOUBLE)
+#define MICROPY_FLOAT_IMPL          (MICROPY_FLOAT_IMPL_FLOAT)
 #define MICROPY_READER_VFS          (0)
 #define MICROPY_PY_PIN              (1)
 #define MICROPY_PY_OS_DUPTERM       (1)