staging:rtl8187se: Fix sparse warning restricted __le16 degrades to integer

This patch fixes the following sparse warning in r8180_core.c - warning:
restricted __le16 degrades to integer. Also, the variable morefrag is
changed to bool as it is being used as a bool.

Signed-off-by: Himangi Saraogi <himangi774@gmail.com>
Reviewed-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>