Simplify debug script and make it more robust

Instead of creating and deleting the breakpoint, create it as a
temporary one from the beginning.

Signed-off-by: Fuad Tabba <tabba@google.com>
Change-Id: I5290caea35227536285292432d7de10e5f136de9
diff --git a/aarch64/aarch64.gdb b/aarch64/aarch64.gdb
index 2e83047..8635d41 100644
--- a/aarch64/aarch64.gdb
+++ b/aarch64/aarch64.gdb
@@ -87,7 +87,7 @@
 file "##ELF_PATH##"
 
 # Break after memory layout constants have been computed.
-break apply_alternatives_all
+tbreak apply_alternatives_all
 commands
 	# Cache kernel constants so they are available regardless
 	# of CurrentEL.
@@ -104,10 +104,6 @@
 	sym_hyp_va _stext
 	add-symbol-file "##ELF_PATH##" $
 
-	# Unset this breakpoint.
-	# Note: this deletes *all* breakpoints.
-	delete breakpoint
-
 	echo Protected KVM debug mode initialized\n
 end