PCI: aardvark: Fix PCIe Max Read Request Size setting

There is an obvious typo issue in the definition of the PCIe maximum
read request size: a bit shift is directly used as a value, while it
should be used to shift the correct value.

Fixes: 8c39d710 ("PCI: aardvark: Add Aardvark PCI host controller driver")
Cc: <stable@vger.kernel.org>
Signed-off-by: Evan Wang <xswang@marvell.com>
Reviewed-by: Victor Gu <xigu@marvell.com>
Reviewed-by: Nadav Haklai <nadavh@marvell.com>
[Thomas: tweak commit log.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>