rockchip: rk3288: grf: Unify speed/flowctrl fields for clarity

Update GMAC speed and flow control fields in GRF_SOC_CON1 to use
RK3288_GMAC_* prefix, ensuring a consistent naming convention. It also
shifts each mask/bit definition to match the actual hardware bits, which
makes future usage easier.

Signed-off-by: Christoph Fritz <chf.fritz@googlemail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
1 file changed