net: mscc: ocelot: expose vsc7514_regmap definition

The VSC7514 target regmap is identical for ones shared with similar
hardware, specifically the VSC7512. Share this resource, and change the
name to match the pattern of other exported resources.

Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com> # regression
Signed-off-by: Jakub Kicinski <kuba@kernel.org>