编码器结构体变量改为static类型

Signed-off-by: huhui <huhui@sharkgulf.com>

Applications/foc/motor/encoder.c

@@ -21,7 +21,7 @@
 
 /* 磁编码器使用一对极的磁铁，所以编码器获取的角度和机械角度相同需要转为电角度*/
 
-encoder_t g_encoder;
+static encoder_t g_encoder;
 
 static __INLINE s16 _abi_count(void) {
 #ifdef ENCODER_CC_INVERT