Staging: rts5139: Fix Sparse Warning for Static Declarations

This patch fixes the following Sparse warnings :
formatter_inquiry_str should be static
queuecommand_lck should be static

Signed-off-by: Monam Agarwal <monamagarwal123@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>