staging: slicoss: clean the spinlock code in slic_entry_open

the locked variable is used for checking whether the function
acquired lock, then unlock. actually with out this we
can achieve the same lock and unlock senario, remove the locked
variable and also cleanup the code around.

Signed-off-by: Devendra Naga <devendra.aaru@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>