crypto: caam - fix build warning when DEBUG_FS not configured

drivers/crypto/caam/ctrl.c: In function 'caam_probe':
drivers/crypto/caam/ctrl.c:55:23: warning: unused variable 'perfmon'

Signed-off-by: Kim Phillips <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

drivers/crypto/caam/ctrl.c

···
 	struct caam_ctrl __iomem *ctrl;
 	struct caam_full __iomem *topregs;
 	struct caam_drv_private *ctrlpriv;
-	struct caam_perfmon *perfmon;
 	struct caam_deco **deco;
 	u32 deconum;
+#ifdef CONFIG_DEBUG_FS
+	struct caam_perfmon *perfmon;
+#endif
 
 	ctrlpriv = kzalloc(sizeof(struct caam_drv_private), GFP_KERNEL);
 	if (!ctrlpriv)