fixes cppcheck:

[cpp_check.py 80 INFO] bsp/w60x/drivers/drv_rtc.c:58:11: error: Syntax Error: AST broken, binary operator '&=' doesn't have two operands. [internalAstError]

[cpp_check.py 80 INFO] libcpu/arm/s3c24x0/rtc.c:34:12: error: Expression 'RTCCON|=RTCCON|=0x01' depends on order of evaluation of side effects [unknownEvaluationOrder]

Author: lygstate

bsp/w60x/drivers/drv_rtc.c

@@ -55,7 +55,7 @@ static int wm_set_timestamp(time_t timestamp)
     gmtime_r(&timestamp, &tblock);
 
     ctrl2  = tls_reg_read32(HR_PMU_RTC_CTRL2);  /* disable */
-    ctrl2 &= ~(1 << 16);
+    ctrl2 &= (int)(~(1 << 16));
     tls_reg_write32(HR_PMU_RTC_CTRL2, ctrl2);
 
     ctrl1 |= tblock.tm_sec;

libcpu/arm/s3c24x0/rtc.c

@@ -31,7 +31,7 @@ void rt_hw_rtc_get(struct tm *ti)
     rt_uint8_t sec, min, hour, mday, wday, mon, year;
 
     /* enable access to RTC registers */
-    RTCCON |= RTC_ENABLE;
+    RTC_ENABLE;
 
     /* read RTC registers */
     do