arm64: dts: meson: fix gxm-khadas-vim2 wifi

Fixes: adc52bf7 ("arm64: dts: meson: fix mmc v2 chips max frequencies")

before

[6.418252] brcmfmac: F1 signature read @0x18000000=0x17224356
[6.435663] brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac4356-sdio for chip BCM4356/2
[6.551259] brcmfmac: brcmf_sdiod_ramrw: membytes transfer failed
[6.551275] brcmfmac: brcmf_sdio_verifymemory: error -84 on reading 2048 membytes at 0x00184000
[6.551352] brcmfmac: brcmf_sdio_download_firmware: dongle image file download failed

after

[6.657165] brcmfmac: F1 signature read @0x18000000=0x17224356
[6.660807] brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac4356-sdio for chip BCM4356/2
[6.918643] brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac4356-sdio for chip BCM4356/2
[6.918734] brcmfmac: brcmf_c_process_clm_blob: no clm_blob available (err=-2), device may have limited channels available
[6.922724] brcmfmac: brcmf_c_preinit_dcmds: Firmware: BCM4356/2 wl0: Jun 16 2015 14:25:06 version 7.35.184.r1 (TOB) (r559293) FWID 01-b22ae69c
Suggested-by: Art Nikpal <email2tema@gmail.com>
Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/1582212790-11402-1-git-send-email-christianshewitt@gmail.com

arch/arm64/boot/dts/amlogic/meson-gxm-khadas-vim2.dts

@@ -327,7 +327,7 @@ &sd_emmc_a {
 	#size-cells = <0>;
 
 	bus-width = <4>;
-	max-frequency = <50000000>;
+	max-frequency = <60000000>;
 
 	non-removable;
 	disable-wp;