util/broadcom: Close file after use

Change-Id: Ieea7ac7fbc618cd12f843f1606f9ebab37cae67e
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Found-by: Coverity Scan #1323508
Reviewed-on: https://review.coreboot.org/17879
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

util/broadcom/secimage/misc.c

@@ -53,5 +53,6 @@ void FillHeaderFromConfigFile(char *h, char *ConfigFileName)
 				h1->Reserved = Reserved;
 			}
 		}
+		fclose(fp);
 	}
 }