Allow enabling SSP for platforms that don't randomize canary

HiSilicon-specific randomization routine for the __stack_chk_guard
should not be called for other platforms that don't implement
this function.
Fix build for targets that don't link with HiSi libraries when
stack smashing protector is enabled.
Signed-off-by: NZbigniew Bodek <zbigniew.bodek@huawei.com>
Change-Id: I1843c897b32991fddc3d0ba362d188c4a621d052

arch/arm/arm/src/los_hw_exc.S

@@ -157,11 +157,14 @@
 @ Description: Stack-Protector Init
 __stack_chk_guard_setup:
     PUSH    {FP, LR}
+#if defined(LOSCFG_PLATFORM_HI3516DV300) || defined(LOSCFG_PLATFORM_HI3518EV300)
+    /* Randomize __stack_chk_quard using platform-specific function. */
     BL      OsRandomStackGuard
     LDR     R1, =__stack_chk_guard
     MOV     R3, R0
     ORR     R2, R3, #0X80000000
     STR     R2, [R1]
+#endif
     POP     {FP, PC}
 #endif