sandbox: Add a flag to set the default log level

It is useful to be able to set the default log level from the command line
when running sandbox. Add a new -L command-line flag for this. The log
level is set using the enum log_level_t in log.h. At present a number must
be specified, e.g. -L7 for debug.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/sandbox/include/asm/state.h b/arch/sandbox/include/asm/state.h
index a612ce8..a96bf44 100644
--- a/arch/sandbox/include/asm/state.h
+++ b/arch/sandbox/include/asm/state.h
@@ -89,6 +89,7 @@
 	enum state_terminal_raw term_raw;	/* Terminal raw/cooked */
 	bool skip_delays;		/* Ignore any time delays (for test) */
 	bool show_test_output;		/* Don't suppress stdout in tests */
+	int default_log_level;		/* Default log level for sandbox */
 
 	/* Pointer to information for each SPI bus/cs */
 	struct sandbox_spi_info spi[CONFIG_SANDBOX_SPI_MAX_BUS]