PCI: rcar: Factor out rcar_pcie_hw_init() call

rcar_pcie_hw_init_{h1|gen2|gen3}() only differ in the PCIe PHY init code
and all end with a call to rcar_pcie_hw_init(), thus it makes sense to
move that call into the driver's probe() method and then rename those
functions to rcar_pcie_phy_init_{h1|gen2|gen3}().

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
[lorenzo.pieralisi@arm.com: updated commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>