rtl8180: Add error check for pci_map_single return value in TX path
rtl8180: Add error check for pci_map_single return value in TX path

Orignal code will not detect a DMA mapping failure, causing the HW
to attempt a DMA from an invalid address.

This patch add the error check and eventually simply drops the TX
packet if we can't map it for DMA.

Signed-off-by: andrea merello <7867dfae3c89ddcc122759b67d7b1e515ee6c0fd@gmail.com>
Signed-off-by: John W. Linville <2a53bac7a5d324865ef46ec4c38b2c0fba1456b4@tuxdriver.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs