If the Gen3 PHY fails to power up, the code does not undo the
initialization caused by phy_init(). Add the missing failure
handling to the rcar_pcie_phy_init_gen3() function.

Fixes: 517ca93a ("PCI: rcar: Add R-Car gen3 PHY support")
Reported-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NMarek Vasut <marek.vasut+renesas@gmail.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NSimon Horman <horms+renesas@verge.net.au>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Phil Edworthy <phil.edworthy@renesas.com>
Cc: Wolfram Sang <wsa@the-dreams.de>