scsi: qla2xxx: Remove unnecessary self assignment

Clang warns when a variable is assigned to itself.

drivers/scsi/qla2xxx/qla_mbx.c:1514:4: warning: explicitly assigning
value of variable of type 'uint64_t' (aka 'unsigned long long') to
itself [-Wself-assign]
        l = l;
        ~ ^ ~
1 warning generated.

This construct is usually used to avoid unused variable warnings, which
I assume is the case here. -Wunused-parameter is hidden behind -Wextra
with GCC 4.6, which is the minimum version to compile the kernel as of
commit cafa0010 ("Raise the minimum required gcc version to 4.6").
Just remove this line to silence Clang.

Link: https://github.com/ClangBuiltLinux/linux/issues/83


Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>