RDMA/bnxt_re: Move the UAPI methods to a dedicated file

RDMA/bnxt_re: Move the UAPI methods to a dedicated file

This is in preparation for upcoming patches in the series.
Driver has to support additional UAPIs for some applications.
Moving current UAPI implementation to a new file, uapi.c.

Link: https://patch.msgid.link/r/20260302110036.36387-2-sriharsha.basavapatna@broadcom.com
Signed-off-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Reviewed-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Sriharsha Basavapatna <sriharsha.basavapatna@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>