TX-abort condition is read and discarded — writes to a non-ACKing slave return SMB_ENOERR success (silent write failure)

Summary

On NACK the DW controller flushes+holds the TX FIFO so TX_NOTFULL stays asserted: every write-path wait passes instantly, bytes are silently flushed, and the done: block reads TX_ABRT_SOURCE into a dead variable - writes to absent slaves return success while reads correctly fail. Configuration/command writes believed delivered when nothing touched the wire. Read-and-surface-the-abort fix.