lcs: get rid of compile warning

-Wunused-but-set-variable generates a compile warning for lcs' tasklet
function. Invoked functions contain already error handling; thus
additional return code checking is not needed here.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>