atl1: fix oops when changing tx/rx ring params

atl1: fix oops when changing tx/rx ring params

Commit 3f5a2a713aad28480d86b0add00c68484b54febc zeroes out the statistics
message block (SMB) and coalescing message block (CMB) when adapter ring
resources are freed.  This is desirable behavior, but, as a side effect,
the commit leads to an oops when atl1_set_ringparam() attempts to alter
the number of rx or tx elements in the ring buffer (by using ethtool
-G, for example).  We don't want SMB or CMB to change during this
operation.

Modify atl1_set_ringparam() to preserve SMB and CMB when changing ring
parameters.

Cc: [email protected]
Signed-off-by: Jay Cliburn <[email protected]>
Reported-by: Tõnu Raitviir <[email protected]>
Signed-off-by: David S. Miller <[email protected]>