infiniband: Remove build hacks

There is not need to keep some build hacks persistent across reboot
infiniband: Remove upstream IB drivers if Mellanox

If we do use the Mellanox driver, it's important to remove the existing
kernel modules to avoid the system to use them.

So we move them out of the tree and insure the depmod is correct.
init.common: Don't probe IB drivers by themselves

It's up to openibd service to determine what kernel modules shall be
loaded or not. Probing them throught modules isn't that good.