[ALSA] Fix compilation without CONFIG_PNP

Fix compilation of some ISA drivers without CONFIG_PNP.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/isa/es18xx.c b/sound/isa/es18xx.c
index bf5de07..08f032b 100644
--- a/sound/isa/es18xx.c
+++ b/sound/isa/es18xx.c
@@ -1878,9 +1878,9 @@
 MODULE_PARM_DESC(dma2, "DMA 2 # for ES18xx driver.");
 
 static struct platform_device *platform_devices[SNDRV_CARDS];
-static int pnp_registered;
 
 #ifdef CONFIG_PNP
+static int pnp_registered;
 
 static struct pnp_card_device_id snd_audiodrive_pnpids[] = {
 	/* ESS 1868 (integrated on Compaq dual P-Pro motherboard and Genius 18PnP 3D) */
@@ -2209,8 +2209,10 @@
 {
 	int i;
 
+#ifdef CONFIG_PNP
 	if (pnp_registered)
 		pnp_unregister_card_driver(&es18xx_pnpc_driver);
+#endif
 	for (i = 0; i < ARRAY_SIZE(platform_devices); ++i)
 		platform_device_unregister(platform_devices[i]);
 	platform_driver_unregister(&snd_es18xx_nonpnp_driver);
@@ -2237,11 +2239,13 @@
 		cards++;
 	}
 
+#ifdef CONFIG_PNP
 	i = pnp_register_card_driver(&es18xx_pnpc_driver);
 	if (i >= 0) {
 		pnp_registered = 1;
 		cards += i;
 	}
+#endif
 
 	if(!cards) {
 #ifdef MODULE