ARC: Cache: Remove per-line I$ operations as unused

ARC: Cache: Remove per-line I$ operations as unused

__cache_line_loop() function was copied from Linux kernel
where per-line instruction cache operations are really used.

In U-Boot we use only entire I$ ops, so we can drop support of
per-line I$ ops from __cache_line_loop() because __cache_line_loop()
is never called with OP_INV_IC parameter.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>