phy: cadence: Sierra: Fix PHY power_on sequence

Commit 39b82338 ("phy: cadence: Add driver for Sierra PHY")
de-asserts PHY_RESET even before the configurations are loaded in
phy_init(). However PHY_RESET should be de-asserted only after
all the configurations has been initialized, instead of de-asserting
in probe. Fix it here.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>