Fix: use int rather than off_t for offsets

Fix: use int rather than off_t for offsets

off_t can be a 64-bit type on 32-bit systems, leading to issues on
32-bit big endian systems (ppc32) where the inline assembler expects a
32-bit register.

There is no point in using off_t here.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I9936a1d8e9b64a51f3e1491f1a23204f1cd9c120