boards: arc: emsdp: fix secure config for emsdp_em7d_esp

emsdp_em7d_esp is a board with secure just like em_starterkit_em7d,
but the secure feature not configed in defconfig file. we need to add
below configs in emsdp_em7d_esp_defconfig files:
    CONFIG_ARC_HAS_SECURE=y
    CONFIG_TRUSTED_EXECUTION_SECURE=y
when secure feature enabled, we use secure timer for system tick, so
we need to add below macro for secure timer:
    #define  IRQ_SEC_TIMER0  20

Signed-off-by: Watson Zeng <zhiwei@synopsys.com>

boards/arc/emsdp/emsdp_em7d_esp_defconfig

@@ -17,3 +17,5 @@ CONFIG_SERIAL=y
 CONFIG_UART_INTERRUPT_DRIVEN=y
 CONFIG_ARC_MPU_ENABLE=y
 CONFIG_GPIO=y
+CONFIG_ARC_HAS_SECURE=y
+CONFIG_TRUSTED_EXECUTION_SECURE=y

soc/arc/snps_emsdp/soc.h

@@ -22,6 +22,8 @@
 /* ARC EM Core IRQs */
 #define IRQ_TIMER0				16
 
+#define IRQ_SEC_TIMER0			20
+
 #ifndef _ASMLANGUAGE
 
 #include <sys/util.h>