PCI: endpoint: functions: Use memcpy_fromio()/memcpy_toio()

Functions copying from/to IO addresses should use the
memcpy_fromio()/memcpy_toio() API rather than plain memcpy().

Fix the issue detected through the sparse tool.

Fixes: 349e7a85

 ("PCI: endpoint: functions: Add an EP function to test PCI")
Suggested-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
[lorenzo.pieralisi@arm.com: updated log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
CC: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
CC: Bjorn Helgaas <bhelgaas@google.com>
CC: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
CC: Niklas Cassel <niklas.cassel@axis.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: Cyrille Pitchen <cyrille.pitchen@free-electrons.com>
CC: linux-pci@vger.kernel.org
CC: linux-kernel@vger.kernel.org