isa_* problems (hgafb is broken since 2.4.13)

[Bakonyi Ferenc]

	Hi!

Calls for isa_memset_io() and isa_writeb() in hga_clear_screen() and 
hga_show_logo() make garbage and bad things since 2.4.13. (Unable to 
handle kernel paging request at virtual address...)
Anybody experiencing problems may want to revert changes made in 
2.4.13. It solves the problem.

I have two questions about asm-i386/io.h:
1. Why #define __ISA_IO_base ((char *)(PAGE_OFFSET)) ?
2. Why not #define __ISA_IO_base ((char *)0) ? 

Regards:
	Ferenc Bakonyi