cnss2: Avoid pci register access after link fail

During PCI resume, if link training fails, avoid accessing
PCI register to set link speed.

Change-Id: I04b243405ebb8e05e4b672ff4fe5f01fede33665
CRs-Fixed: 2474888
Signed-off-by: Mahesh Kumar Kalikot Veetil <mkalikot@codeaurora.org>