tcl/target, board: remove useless gdb-attach event definitions

Since commit bae76053dc
gdb-attach event is defined as halt by default.
Remove useless and in case of bcm281xx wrong definitions of the event.

Change-Id: I8e69780a93722eb9392673303f54d502e71eceb6
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: http://openocd.zylin.com/4763
Tested-by: jenkins
Reviewed-by: Steven Stallion <sstallion@gmail.com>

tcl/target/u8500.cfg

@@ -206,10 +206,6 @@ dap create $_CHIPNAME.dap -chain-position $_CHIPNAME.cpu
 
 target create $_TARGETNAME_1 cortex_a -dap $_CHIPNAME.dap -dbgbase $_DAP_DBG1 -coreid 0 -rtos linux
 
-$_TARGETNAME_1 configure -event gdb-attach {
-	halt
-}
-
 
 if { ![info exists TARGETNAME_2] } {
 global _TARGETNAME_2
@@ -221,10 +217,6 @@ set _TARGETNAME_2 $TARGETNAME_2
 
 target create $_TARGETNAME_2 cortex_a -dap $_CHIPNAME.dap -dbgbase $_DAP_DBG2 -coreid 1 -rtos linux
 
-$_TARGETNAME_2 configure -event gdb-attach {
-	halt
-}
-
 
 if {![info exists SMP]} {
 global _SMP