RDMA/rxe: Remove redundant assignment to variable page_offset

RDMA/rxe: Remove redundant assignment to variable page_offset

The variable page_offset is being assigned a value at the start of
a loop and being redundantly zero'd at the end of the loop, there
is no code that reads the zero'd value. The assignment is redundant
and can be removed.

Signed-off-by: Colin Ian King <coking@nvidia.com>
Link: https://patch.msgid.link/20251014120343.2528608-1-coking@nvidia.com
Reviewed-by: Zhu Yanjun <yanjun.zhu@linux.dev>
Signed-off-by: Leon Romanovsky <leon@kernel.org>