[media] lmedm04: change some static variables to automatic

ibuf and rbuf in lme2510_int_response are always assigned to before they
are read, and their addresses do not escape the function, so they have
no reason to be static.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>