cxgb4: Remove unused cxgb4_get_srq_entry

cxgb4: Remove unused cxgb4_get_srq_entry

cxgb4_get_srq_entry() has been unused since 2018's commit
e47094751ddc ("cxgb4: Add support to initialise/read SRQ entries")
which added it.

Remove it.

Note: I'm a bit suspicious whether any of the srq code in there
actually does anything useful;  without this get I can't see anything
that reads the data, so perhaps the whole thing should go?
But that however would remove one of the opcode handlers, and I have
no way to test that.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Link: https://patch.msgid.link/20241013203831.88051-4-linux@treblig.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>