[target]: Add code to get LINUX_MACHTYPE by calling a function for all targets

Add code to read the hardware platform and return the corresponding
LINUX_MACHTYPE for msm7630_surf target.
diff --git a/target/qsd8250_surf/init.c b/target/qsd8250_surf/init.c
index d63c9e4..9769a4c 100644
--- a/target/qsd8250_surf/init.c
+++ b/target/qsd8250_surf/init.c
@@ -36,6 +36,8 @@
 #include <lib/ptable.h>
 #include <dev/flash.h>
 
+#define LINUX_MACHTYPE  1008000
+
 static struct ptable flash_ptable;
 
 /* for these partitions, start will be offset by either what we get from
@@ -110,3 +112,8 @@
 	ptable_dump(&flash_ptable);
 	flash_set_ptable(&flash_ptable);
 }
+
+unsigned board_machtype(void)
+{
+    return LINUX_MACHTYPE;
+}