Keep HSI16 working in stop mode. (#2621)

firmware/targets/f7/furi_hal/furi_hal_clock.c

@@ -144,6 +144,7 @@ void furi_hal_clock_init() {
     LL_RCC_SetRNGClockSource(LL_RCC_RNG_CLKSOURCE_CLK48);
     LL_RCC_SetUSBClockSource(LL_RCC_USB_CLKSOURCE_PLLSAI1);
     LL_RCC_SetCLK48ClockSource(LL_RCC_CLK48_CLKSOURCE_PLLSAI1);
+    LL_RCC_HSI_EnableInStopMode(); // Ensure that MR is capable of work in STOP0
     LL_RCC_SetSMPSClockSource(LL_RCC_SMPS_CLKSOURCE_HSE);
     LL_RCC_SetSMPSPrescaler(LL_RCC_SMPS_DIV_1);
     LL_RCC_SetRFWKPClockSource(LL_RCC_RFWKP_CLKSOURCE_LSE);
@@ -207,8 +208,8 @@ void furi_hal_clock_switch_to_hsi() {
     while(!LL_RCC_HSI_IsReady())
         ;
 
-    LL_RCC_SetSysClkSource(LL_RCC_SYS_CLKSOURCE_HSI);
     LL_RCC_SetSMPSClockSource(LL_RCC_SMPS_CLKSOURCE_HSI);
+    LL_RCC_SetSysClkSource(LL_RCC_SYS_CLKSOURCE_HSI);
 
     while(LL_RCC_GetSysClkSource() != LL_RCC_SYS_CLKSOURCE_STATUS_HSI)
         ;

firmware/targets/f7/furi_hal/furi_hal_power.c

@@ -94,6 +94,7 @@ void furi_hal_power_init() {
 
     LL_PWR_SetRegulVoltageScaling(LL_PWR_REGU_VOLTAGE_SCALE1);
     LL_PWR_SMPS_SetMode(LL_PWR_SMPS_STEP_DOWN);
+
     LL_PWR_SetPowerMode(FURI_HAL_POWER_STOP_MODE);
     LL_C2_PWR_SetPowerMode(FURI_HAL_POWER_STOP_MODE);