ARC: use ASL assembler mnemonic

commit a6416f57ce57fb390b6ee30b12c01c29032a26af upstream.

ARCompact and ARCv2 only have ASL, while binutils used to support LSL as
a alias mnemonic.

Newer binutils (upstream) don't want to do that so replace it.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>