The quirks attribute is not available on older kernels.

--- a/drivers/net/wireless/libertas/if_sdio.c
+++ b/drivers/net/wireless/libertas/if_sdio.c
@@ -777,6 +777,7 @@ static int if_sdio_power_on(struct if_sd
 	if (ret)
 		goto release;
 
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,32))
 	/* For 1-bit transfers to the 8686 model, we need to enable the
 	 * interrupt flag in the CCCR register. Set the MMC_QUIRK_LENIENT_FN0
 	 * bit to allow access to non-vendor registers. */
@@ -795,6 +796,7 @@ static int if_sdio_power_on(struct if_sd
 		if (ret)
 			goto disable;
 	}
+#endif
 
 	card->ioport = sdio_readb(func, IF_SDIO_IOPORT, &ret);
 	if (ret)
--- a/drivers/net/wireless/mwifiex/sdio.c
+++ b/drivers/net/wireless/mwifiex/sdio.c
@@ -77,7 +77,9 @@ mwifiex_sdio_probe(struct sdio_func *fun
 
 	card->func = func;
 
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,34))
 	func->card->quirks |= MMC_QUIRK_BLKSZ_FOR_BYTE_MODE;
+#endif
 
 	sdio_claim_host(func);
 	ret = sdio_enable_func(func);