new non-OS SDK addition

[scaprile]

hi there,
the new SDK for non-OS requires this function to be added in user_main:
`
/******************************************************************************

• FunctionName : user_rf_cal_sector_set

• Description : SDK just reversed 4 sectors, used for rf init data and paramters.

•            We add this function to force users to set rf cal sector, since
  

•            we don't know which sector is free in user's application.
  

•            sector map for last several sectors : ABBBCDDD
  

•            A : rf cal
  

•            B : at parameters
  

•            C : rf init data
  

•            D : sdk parameters
  

• Parameters : none

• Returns : rf cal sector
  *******************************************************************************/
  uint32 ICACHE_FLASH_ATTR
  user_rf_cal_sector_set(void)
  {
  enum flash_size_map size_map = system_get_flash_size_map();
  uint32 rf_cal_sec = 0;

  switch (size_map) {
  case FLASH_SIZE_4M_MAP_256_256:
  rf_cal_sec = 128 - 8;
  break;

  case FLASH_SIZE_8M_MAP_512_512:
      rf_cal_sec = 256 - 5;
      break;
  
  case FLASH_SIZE_16M_MAP_512_512:
  case FLASH_SIZE_16M_MAP_1024_1024:
      rf_cal_sec = 512 - 5;
      break;
  
  case FLASH_SIZE_32M_MAP_512_512:
  case FLASH_SIZE_32M_MAP_1024_1024:
      rf_cal_sec = 1024 - 5;
      break;
  
  default:
      rf_cal_sec = 0;
      break;
  

  }

  return rf_cal_sec;
  }
  `

I don't know if it needs mods in your specific code, I just made it to compilation and haven't tested any further.
Regards.