staging: media: atomisp: fix range checking on clk_num

The range checking on clk_num is incorrect; fix these so that invalid
clk_num values are detected correctly.

Detected by static analysis with by PVS-Studio

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>