sandbox: Support multiple reset types

Add settings for the last reset generated, and the types of resets which
are permitted. This will be used for testing.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/sandbox/cpu/state.c b/arch/sandbox/cpu/state.c
index cae731c..7e5d03e 100644
--- a/arch/sandbox/cpu/state.c
+++ b/arch/sandbox/cpu/state.c
@@ -345,6 +345,10 @@
 	state->ram_buf = os_malloc(state->ram_size);
 	assert(state->ram_buf);
 
+	/* No reset yet, so mark it as such. Always allow power reset */
+	state->last_reset = RESET_COUNT;
+	state->reset_allowed[RESET_POWER] = true;
+
 	/*
 	 * Example of how to use GPIOs:
 	 *