Replace CTLFLAG_NEEDGIANT with CTLFLAG_MPSAFE for all interrupt
coalescing sysctls. The driver uses jme_mtx mutex for proper
synchronization and does not require Giant lock.
Sysctls converted:
- dev.jme.X.tx_coal_to (TX coalescing timeout)
- dev.jme.X.tx_coal_pkt (TX coalescing packet count)
- dev.jme.X.rx_coal_to (RX coalescing timeout)
- dev.jme.X.rx_coal_pkt (RX coalescing packet count)
- dev.jme.X.process_limit (max RX events to process)