DEV: @drv s25fs driver has erase functionality

 - Erase functionality support sector erase only (4-byte addressing)
 - _ioctl support global CTRL_XXX commands and local
DEV: @s25fs Comments added
FIX: @drv ioctl_buf_t parameter calling fixing after 13df2b7
DEV: @s25fs Global CTRL_XXX defines added to support see module.
DEV: @see Added link to FLASH sub system data. r/w ENCH part 1

 - The see module has a void* flash pointer to link with the flash data
   struct of the subsystem. In case of simple implementation or hardware
   flash module it can be (void*)0.
 - The read/write operations take tooooooo looooong to find the last
   written data. So we start to implement a faster algorithm