log: add category LOGC_EFI

The EFI implementation does not fit into any of the existing categories.

Provide LOGC_EFI so that EFI related message can be filtered.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/common/log.c b/common/log.c
index 1b1b98e..680a60f 100644
--- a/common/log.c
+++ b/common/log.c
@@ -21,6 +21,7 @@
 	"core",
 	"driver-model",
 	"device-tree",
+	"efi",
 };
 
 static const char *log_level_name[LOGL_COUNT] = {