armv7m: disable icache before linux booting

Similarly to ARMV7, on ARMV7M instruction cache memory needs
to be disabled before running linux kernel to avoid kernel to
be stuck.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>

arch/arm/cpu/armv7m/cpu.c

@@ -37,6 +37,9 @@ int cleanup_before_linux(void)
 	 * dcache flushing and disabling dcache */
 	invalidate_dcache_all();
 
+	icache_disable();
+	invalidate_icache_all();
+
 	return 0;
 }