external/mambo: add shortcut to print all GPRs

The 'p' function added by mambo utils can be used to print registers
(GPR or SPR) from a thread. Mambo supports printing all the GPRs in one
go so this plumbs it into the 'p' function.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

external/mambo/mambo_utils.tcl

@@ -4,6 +4,10 @@
 #
 proc p { reg { t 0 } { c 0 } } {
     switch -regexp $reg {
+	^r$ {
+            set val [mysim cpu $c thread $t display gprs]
+            puts "$val"
+	}
         ^r[0-9]+$ {
             regexp "r(\[0-9\]*)" $reg dummy num
             set val [mysim cpu $c thread $t display gpr $num]