raw: test against runtime value of max_raw_minors

bind_get() checks the device number it is called with. It uses
MAX_RAW_MINORS for the upper bound. But MAX_RAW_MINORS is set at compile
time while the actual number of raw devices can be set at runtime. This
means the test can either be too strict or too lenient. And if the test
ends up being too lenient bind_get() might try to access memory beyond
what was allocated for "raw_devices".

So check against the runtime value (max_raw_minors) in this function.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Acked-by: Jan Kara <jack@suse.cz>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>