media: pci: cx88-input: use 64-bit arithmetic instead of 32-bit

Add suffix LL to constant 1000000 in order to give the compiler
complete information about the proper arithmetic to use. Notice
that this constant is used in a context that expects an expression
of type ktime_t (64 bits, signed).

The expression ir->polling * 1000000 is currently being evaluated
using 32-bit arithmetic.

Addresses-Coverity-ID: 1392628 ("Unintentional integer overflow")
Addresses-Coverity-ID: 1392630 ("Unintentional integer overflow")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>