revert not needed change

components/hal/include/hal/i2c_hal.h

@@ -98,7 +98,6 @@ void _i2c_hal_set_bus_timing(i2c_hal_context_t *hal, int scl_freq, i2c_clock_sou
 #if SOC_PERIPH_CLK_CTRL_SHARED
 /// use a macro to wrap the function, force the caller to use it in a critical section
 /// the critical section needs to declare the __DECLARE_RCC_ATOMIC_ENV variable in advance
-int __DECLARE_RCC_ATOMIC_ENV __attribute__ ((unused)); // To avoid build errors/warnings about __DECLARE_RCC_ATOMIC_ENV
 #define i2c_hal_set_bus_timing(...) do {(void)__DECLARE_RCC_ATOMIC_ENV; _i2c_hal_set_bus_timing(__VA_ARGS__);} while(0)
 #else
 #define i2c_hal_set_bus_timing(...)   _i2c_hal_set_bus_timing(__VA_ARGS__)