linux-phytec-ti

HACK: net: ethernet: ti: cpts: add return value to tx and rx timestamp funcitons

Added return values in tx and rx timestamp funcitons facilitate the
possibililies of timestamping by CPSW modules other than CPTS, such as
packet accelerator on Keystone 2 devices.

LKML link:
 - https://patchwork.kernel.org/patch/9331419/
 not accepted, so HACK.

Signed-off-by: WingMan Kwok <w-kwok2@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>