HID: intel-ish-hid: ishtp-fw-loader: Fix a kernel-doc formatting issue

This function had kernel-doc that not used a hash to separate
the function name from the one line description.

The warning was found by running scripts/kernel-doc, which is
caused by using 'make W=1'.

drivers/hid/intel-ish-hid/ishtp-fw-loader.c:271: warning: This comment
starts with '/**', but isn't a kernel-doc comment. Refer
Documentation/doc-guide/kernel-doc.rst

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>