brcmfmac: properly align buffers on certain platforms with 64 bit DMA

Systems with 64 bit DMA at least partially require buffers to be used
for DMA to be 8-byte-aligned. One example is Amlogic Meson GX.
Switching the MMC/SDIO driver for this platform to SG DMA mode
resulted in problems due to unaligned buffers.

Fortunately the brcmfmac driver has a global define for the alignment.
Changing it to 8 fixed the issues with Meson GX.
Suggested-by: NHelmut Klein <hgkr.klein@gmail.com>
Tested-by: NHelmut Klein <hgkr.klein@gmail.com>
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NKalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c

@@ -540,7 +540,11 @@ static int qcount[NUMPRIO];
 /* Limit on rounding up frames */
 static const uint max_roundup = 512;
 
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+#define ALIGNMENT  8
+#else
 #define ALIGNMENT  4
+#endif
 
 enum brcmf_sdio_frmtype {
 	BRCMF_SDIO_FT_NORMAL,