Fix more argc checks

Signed-off-by: Aditya Deshpande <aditya.deshpande@arm.com>
diff --git a/programs/hash/generic_sum.c b/programs/hash/generic_sum.c
index e2e49e3..995694a 100644
--- a/programs/hash/generic_sum.c
+++ b/programs/hash/generic_sum.c
@@ -169,7 +169,7 @@
 
     mbedtls_md_init(&md_ctx);
 
-    if (argc == 1) {
+    if (argc < 2) {
         const int *list;
 
         mbedtls_printf("print mode:  generic_sum <mbedtls_md> <file> <file> ...\n");