net: phy: mediatek-ge-soc: sync driver with MediaTek SDK

net: phy: mediatek-ge-soc: sync driver with MediaTek SDK

Sync initialization and calibration routines with MediaTek's reference
driver. Improves compliance and resolves link stability issues with
CH340 IoT devices connected to MT798x built-in PHYs.

Fixes: 98c485eaf509 ("net: phy: add driver for MediaTek SoC built-in GE PHYs")
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Link: https://lore.kernel.org/r/f2195279c234c0f618946424b8236026126bc595.1706071311.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>