libbladeRF: Fixed incorrect buffer resubmission on SW RX overrun (sync i/f)

The handling of RX overruns in the sync interface was logically flawed;
attempting to resubmit a transfer without invalidating the remaining
in-flight transfers would cause transfers to become out of order.

When a SW RX overrun is detected, all transfers are now resubmitted to
maintain proper ordering.
libbladeRF: Warning cleanup - fixes broken Windows build
libbladeRF: Fixed dereferences before NULL checks

Resolves CIDs 1195477 and 1195478
libbladeRF: Removed dead code (addresses CID 1195476)