MIPS: SEAD3: Enable LL/SC.

All synthesizable CPU cores that could be loaded into a SEAD3's FPGA are
MIPS32 or MIPS64 CPUs that have ll/sc.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/mach-sead3/cpu-feature-overrides.h

@@ -28,7 +28,7 @@
 /* #define cpu_has_prefetch	? */
 #define cpu_has_mcheck		1
 /* #define cpu_has_ejtag	? */
-#define cpu_has_llsc		0
+#define cpu_has_llsc		1
 /* #define cpu_has_vtag_icache	? */
 /* #define cpu_has_dc_aliases	? */
 /* #define cpu_has_ic_fills_f_dc ? */