Staging: sbe-2t3e3: Fix smatch warning of function definition with external linkage

This patch fixes the following smatch warning in cpld.c-
drivers/staging/sbe-2t3e3/cpld.c:243:13: warning: function 'cpld_set_clock' with external linkage has definition

Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>