make convenience pointer to global structs const

stm-firmware/main.c

@@ -58,11 +58,8 @@ static void setup_nvic_priorities()
 	NVIC_SetPriority(DMA2_Stream7_IRQn, 3);
 }
 
-/* Process parameters are defined static globally to be watched in debugger from any context */
-static float target_temperature;
-
 FATFS fs;
-FATFS *fs_ptr = &fs;
+FATFS * const fs_ptr = &fs;
 
 static inline void uart_gpio_config()
 {
@@ -209,8 +206,6 @@ int main()
 	uint64_t quarter_sec_timestamp = 0ULL;
 	enum safety_adc_check_result safety_adc_status;
 
-	target_temperature = 25.0f;
-
 	zero_ccm_ram();
 	setup_system();