cxgb4: Enhance driver to update FW, when FW is too old

t4_check_fw_version() can return several error codes (-EINVAL, -EBUSY,
-EAGAIN). The present code sets the adapter state to UNINIT only if its
an EFAULT. In all the error cases set the adapter to uninitialized state.

In t4_check_fw_version() if call to t4_get_fw_version() fails, repeat the
operation a few times before returning failure.

Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>