bricks/_common/arm_none_eabi: omit readline on move hub

This reduces the firmware size by avoiding adding root pointers for the
unused readline code on Move hub.

Author: dlech

bricks/_common/arm_none_eabi.mk

@@ -199,14 +199,18 @@ include $(PBTOP)/bricks/_common/sources.mk
 
 PY_EXTRA_SRC_C = $(addprefix shared/,\
 	libc/string0.c \
-	readline/readline.c \
 	runtime/gchelper_native.c \
 	runtime/interrupt_char.c \
 	runtime/pyexec.c \
 	runtime/stdout_helpers.c \
 	runtime/sys_stdio_mphal.c \
 	)
 
+ifneq ($(PBIO_PLATFORM),move_hub)
+# to avoid adding unused root pointers
+PY_EXTRA_SRC_C += shared/readline/readline.c
+endif
+
 PY_EXTRA_SRC_C += $(addprefix bricks/_common/,\
 	micropython.c \
 	)