p9100: use standard fields for framebuffer physical address and length

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 are displayed correctly.

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>