PNP: add printf attribute to log function

Attributing the function allows the compiler to more thoroughly
check the use of the function with -Wformat and similar flags.

Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/pnp/interface.c

@@ -33,6 +33,7 @@ struct pnp_info_buffer {
 
 typedef struct pnp_info_buffer pnp_info_buffer_t;
 
+__printf(2, 3)
 static int pnp_printf(pnp_info_buffer_t * buffer, char *fmt, ...)
 {
 	va_list args;