Fix problems with ld version 2.16 (dot outside sections problem)

Pointed out by Gerhard Jaeger, 31 Aug 2005;
cf. http://sourceware.org/ml/binutils/2005-08/msg00412.html

board/canmb/u-boot.lds

@@ -93,11 +93,13 @@ SECTIONS
   _edata  =  .;
   PROVIDE (edata = .);
 
+  . = .;
   __u_boot_cmd_start = .;
   .u_boot_cmd : { *(.u_boot_cmd) }
   __u_boot_cmd_end = .;
 
 
+  . = .;
   __start___ex_table = .;
   __ex_table : { *(__ex_table) }
   __stop___ex_table = .;