[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/surf-msm7k/init.c b/target/surf-msm7k/init.c
index e559ef8..956ea49 100644
--- a/target/surf-msm7k/init.c
+++ b/target/surf-msm7k/init.c
@@ -37,6 +37,8 @@
 
 #define BOARD_FLASH_OFFSET	378
 
+#define LINUX_MACHTYPE  0x0000059F
+
 static struct ptable flash_ptable;
 
 /* for these partitions, start will be offset by either what we get from
@@ -111,3 +113,8 @@
 	ptable_dump(&flash_ptable);
 	flash_set_ptable(&flash_ptable);
 }
+
+unsigned board_machtype(void)
+{
+    return LINUX_MACHTYPE;
+}