[U-Boot] errno.h header -> asm-generic?

Hi All,

I found that Microblaze miss errno.h file among some other minor fault which I want to fix.

Anyway I looked at errno.h header file for all arch which are in U-BOOT and I found that almost all arch use the same file that's why I think that will be good to create (maybe asm-generic) folder with these type of generic file.

What do you think guys?

Thanks, Michal