webassembly/Makefile: Remove --memory-init-file from linker options.

It's no longer supported by Emscripten (at least at 3.1.55).  And it's not
needed when the output is WASM, which it is by default.

Signed-off-by: Damien George <damien@micropython.org>

ports/webassembly/Makefile

@@ -38,7 +38,6 @@ OBJ += $(addprefix $(BUILD)/, $(SRC_C:.c=.o))
 JSFLAGS += -s ASYNCIFY
 JSFLAGS += -s EXPORTED_FUNCTIONS="['_mp_js_init', '_mp_js_init_repl', '_mp_js_do_str', '_mp_js_process_char', '_mp_hal_get_interrupt_char', '_mp_sched_keyboard_interrupt']"
 JSFLAGS += -s EXPORTED_RUNTIME_METHODS="['ccall', 'cwrap', 'FS']"
-JSFLAGS += -s --memory-init-file 0
 JSFLAGS += --js-library library.js
 
 all: $(BUILD)/micropython.js