IB/qib: Move char *qib_sdma_state_names[] and constify while there.

Note: This is compile only tested as I have no access to the hw.
This variable was not used in qib_sdma.c but in qib_iba7322.c. Declaring it
there, as static, saves 56 bytes.

add/remove: 0/2 grow/shrink: 0/0 up/down: 0/-144 (-144)
Function                                     old     new   delta
qib_sdma_state_names                          56       -     -56
qib_sdma_event_names                          88       -     -88
Total: Before=2874565, After=2874421, chg -0.01%

Signed-off-by: Hernán Gonzalez <hernan@vanguardiasur.com.ar>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>