net: stmmac: sunxi: use stmmac_pltfr_probe()

Rather than open-coding the calls to sun7i_gmac_init() and
sun7i_gmac_exit() in the probe function, use stmmac_pltfr_probe()
which will automatically call the plat_dat->init() and plat_dat->exit()
methods appropriately. This simplifies the code.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1u4frZ-000nMl-BB@rmk-PC.armlinux.org.uk


Signed-off-by: Jakub Kicinski <kuba@kernel.org>