vboot_ref/flashrom_drv: Allow sentinel verbosity value

Allow for picking the default verbosity with a sentinel
value of -1.

BUG=b:207808292
BRANCH=none
TEST=none

Signed-off-by: Edward O'Callaghan <quasisec@google.com>
Change-Id: Ia3a21e8647fe480c60ea80ecb060466e9d86110a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/3461094
Tested-by: Edward O'Callaghan <quasisec@chromium.org>
Auto-Submit: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-by: Nikolai Artemiev <nartemiev@google.com>
Commit-Queue: Nikolai Artemiev <nartemiev@google.com>
diff --git a/host/lib/flashrom_drv.c b/host/lib/flashrom_drv.c
index 0225047..883b6d3 100644
--- a/host/lib/flashrom_drv.c
+++ b/host/lib/flashrom_drv.c
@@ -52,7 +52,7 @@
 	int r = 0;
 	size_t len = 0;
 
-	g_verbose_screen = verbosity;
+	g_verbose_screen = (verbosity == -1) ? FLASHROM_MSG_INFO : verbosity;
 
 	char *programmer, *params;
 	char *tmp = flashrom_extract_params(image->programmer, &programmer, &params);
@@ -117,7 +117,7 @@
 	int r = 0;
 	size_t len = 0;
 
-	g_verbose_screen = verbosity;
+	g_verbose_screen = (verbosity == -1) ? FLASHROM_MSG_INFO : verbosity;
 
 	char *programmer, *params;
 	char *tmp = flashrom_extract_params(image->programmer, &programmer, &params);