qlogic/qed: Constify *pkt_type_str[]

Note: This is compile only tested as I have no access to the hw.
Constifying and declaring as static saves 24 bytes.

add/remove: 0/1 grow/shrink: 0/0 up/down: 0/-24 (-24)
Function                                     old     new   delta
pkt_type_str                                  24       -     -24
Total: Before=3599256, After=3599232, chg -0.00%

Signed-off-by: Hernán Gonzalez <hernan@vanguardiasur.com.ar>
Acked-by: Michal Kalderon <michal.kalderon@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>