ACPI: clean up video.c boundary checks and types

proc.c and video.c are a bit sloppy around types and style,
confusing gcc for a new feature that'll be in 2.6.33 and will
cause a warning on the current code.

This patch changes

if  (foo + 1 > sizeof bar)

into

if (foo >= sizeof(bar))

which is more kernel-style.

it also changes a variable in proc.c to unsigned; it gets assigned
a value from an unsigned type, and is then only compared for > not
for negative, so using unsigned is just outright the right type

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>