PCI: mvebu: Remove duplicate of_clk_get_by_name() call

Probably due to a merge conflict resolution gone bad, the PCI clock is
got twice.  Remove the redundant call of of_clk_get_by_name().

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Jason Cooper <jason@lakedaemon.net>