selftests/powerpc: Add missing binaries to .gitignores

Some of the recent new selftests were missing additions to .gitignore,
add them now.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

tools/testing/selftests/powerpc/math/.gitignore

@@ -4,3 +4,4 @@ fpu_preempt
 vmx_preempt
 fpu_signal
 vmx_signal
+vsx_preempt

tools/testing/selftests/powerpc/signal/.gitignore

+signal
+signal_tm

tools/testing/selftests/powerpc/tm/.gitignore

@@ -7,3 +7,7 @@ tm-fork
 tm-tar
 tm-tmspr
 tm-exec
+tm-signal-context-chk-fpu
+tm-signal-context-chk-gpr
+tm-signal-context-chk-vmx
+tm-signal-context-chk-vsx