cnss2: Use sysfs_remove_link instead of sysfs_delete_link

sysfs_remove_link() is a GPL export API hence use it instead
of sysfs_delete_link().

Change-Id: Ib2e4c9c22be01a9108bb07952b9fbf940a0a2df4
Signed-off-by: Yue Ma <yuem@codeaurora.org>