net: stmmac: consolidate version reading and validation

net: stmmac: consolidate version reading and validation

There is no need to read the version register twice, once in
stmmac_get_id() and then again in stmmac_get_dev_id(). Consolidate
this into stmmac_get_version() and pass each of these this value.

As both functions unnecessarily issue the same warning for a zero
register value, also move this into stmmac_get_version().

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Tested-by: Mohd Ayaan Anwar <mohd.anwar@oss.qualcomm.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1vDteq-0000000CCC3-3zbJ@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>