powerpc/sysfs: Remove unused 'err' variable in sysfs_create_dscr_default()

This fixes a compile error with W=1.

arch/powerpc/kernel/sysfs.c: In function ‘sysfs_create_dscr_default’:
arch/powerpc/kernel/sysfs.c:228:7: error: variable ‘err’ set but not used [-Werror=unused-but-set-variable]
   int err = 0;
       ^~~
cc1: all warnings being treated as errors

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200914211007.2285999-2-clg@kaod.org

arch/powerpc/kernel/sysfs.c

@@ -217,14 +217,13 @@ static DEVICE_ATTR(dscr_default, 0600,
 static void sysfs_create_dscr_default(void)
 {
 	if (cpu_has_feature(CPU_FTR_DSCR)) {
-		int err = 0;
 		int cpu;
 
 		dscr_default = spr_default_dscr;
 		for_each_possible_cpu(cpu)
 			paca_ptrs[cpu]->dscr_default = dscr_default;
 
-		err = device_create_file(cpu_subsys.dev_root, &dev_attr_dscr_default);
+		device_create_file(cpu_subsys.dev_root, &dev_attr_dscr_default);
 	}
 }
 #endif /* CONFIG_PPC64 */