[U-Boot] [fw_printenv should open device as O_SYNC]

[Mari Ivan-AIM018]

Hi all,
 
We have hit the following issue in a board with 2 flash banks.
 
First I set some env variable in U-boot, using fw_setenv, then
immediately I switch the banks. But as the buffers have not yet been
flushed to the mtd driver, the bank switching leaves the flash in
corrupted state.
 
I ve modified the fw_env.c file to open the mtd O_SYNC and it works
fine.
 
If it is OK I can submit a patch for this.
 
 
Regards,
 
Ivan