Linuxbios, bugfix in sis flash_rom

[Felix Kloeckner]

Hello,

after wondering why flash_rom wasn't working, i found that the compiler
did some optimization on the reading/writing from/to the flash. So i
made the variables for accessing the flash 'volatile', now it works!

could you apply the patch to the linuxbios cvs?

thanks

Felix Kloeckner

ps

this patch is for jedec flash only, other parts probably have the
same problem