py/emitinlinerv32: Fix compilation with ESP-IDF v5.2 and later.

This commit fixes a compilation warning (turned error) about a
potentially uninitialised variable being used.  The warning can be
ignored as the variable in question is always written to, but the code
has been changed to silence that warning.

Signed-off-by: Alessandro Gatti <a.gatti@frob.it>

Author: agatti

py/emitinlinerv32.c

@@ -709,9 +709,11 @@ static bool handle_load_store_opcode_with_offset(emit_inline_asm_t *emit, qstr o
         return false;
     }
 
-    mp_uint_t rd;
-    mp_uint_t rs1;
-    parse_register_node(nodes[0], &rd, opcode_data->argument1_kind & C);
+    mp_uint_t rd = 0;
+    mp_uint_t rs1 = 0;
+    if (!parse_register_node(nodes[0], &rd, opcode_data->argument1_kind & C)) {
+        return false;
+    }
     if (!parse_register_node(nodes[1], &rs1, opcode_data->argument3_kind & C)) {
         return false;
     }