net: sis: remove leading spaces before tabs

There are a few leading spaces before tabs and remove it by running the
following commard:

	$ find . -name '*.c' | xargs sed -r -i 's/^[ ]+\t/\t/'
	$ find . -name '*.h' | xargs sed -r -i 's/^[ ]+\t/\t/'

Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Signed-off-by: Hui Tang <tanghui20@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>