Use standard fields fbinfo.fix.smem_start and fbinfo.fix.smem_len
for physical address and length of framebuffer.

This also fixes output of the 'fbset -i' command - address and length
of the framebuffer is displayed correctly.
Signed-off-by: NKrzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>