net: Fix client identifiers for ARM

There are client identifiers specifically reserved for ARM U-Boot
according to http://www.ietf.org/assignments/dhcpv6-parameters/dhcpv6-parameters.xml#processor-architecture.

So let's actually make use of them rather than the bogus 0x100 that
we emitted so far.

Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Tom Rini <trini@konsulko.com>
[trini: Drop the Xilinx define to 0x100 as it's not the correct value to
use].
Signed-off-by: Tom Rini <trini@konsulko.com>

include/configs/xilinx_zynqmp.h

@@ -80,7 +80,6 @@
 #define CONFIG_BOOTP_DNS
 #define CONFIG_BOOTP_PXE
 #define CONFIG_BOOTP_SUBNETMASK
-#define CONFIG_BOOTP_PXE_CLIENTARCH     0x100
 
 /* Diff from config_distro_defaults.h */
 #define CONFIG_SUPPORT_RAW_INITRD

net/Kconfig

@@ -34,7 +34,8 @@ config NET_TFTP_VARS
 
 config BOOTP_PXE_CLIENTARCH
 	hex
-        default 0x100 if ARM
+        default 0x16 if ARM64
+        default 0x15 if ARM
         default 0 if X86
 
 config BOOTP_VCI_STRING