x86/resctrl: Add printf attribute to log function

Mark the function with the __printf attribute to allow the compiler to
more thoroughly typecheck its arguments against a format string with
-Wformat and similar flags.

 [ bp: Massage commit message. ]
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20201221160009.3752017-1-trix@redhat.com

arch/x86/kernel/cpu/resctrl/internal.h

@@ -572,6 +572,7 @@ union cpuid_0x10_x_edx {
 
 void rdt_last_cmd_clear(void);
 void rdt_last_cmd_puts(const char *s);
+__printf(1, 2)
 void rdt_last_cmd_printf(const char *fmt, ...);
 
 void rdt_ctrl_update(void *arg);