V4L/DVB (5023): Fix compilation on ppc32 architecture

There's a problem, pointed by Meelis Roos <mroos@linux.ee>, that, on ppc32 arch,
with some gcc versions (noticed with prerelease 4.1.2 20061115), compilation 
fails, due the lack of __ucmpdi2 to do the required 64-bit comparision.
This patch takes some sugestions made by Andrew Morton <akpm@osdl.org>,
Stelian Pop <stelian@popies.net> and Segher Boessenkool <segher@kernel.crashing.org>

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>