spi_flash_cache_enabled: report correct result in single core mode

components/spi_flash/cache_utils.c

@@ -287,6 +287,9 @@ static void IRAM_ATTR spi_flash_restore_cache(uint32_t cpuid, uint32_t saved_sta
 
 IRAM_ATTR bool spi_flash_cache_enabled()
 {
-    return DPORT_REG_GET_BIT(DPORT_PRO_CACHE_CTRL_REG, DPORT_PRO_CACHE_ENABLE)
-        && DPORT_REG_GET_BIT(DPORT_APP_CACHE_CTRL_REG, DPORT_APP_CACHE_ENABLE);
+    bool result = (DPORT_REG_GET_BIT(DPORT_PRO_CACHE_CTRL_REG, DPORT_PRO_CACHE_ENABLE) != 0);
+#if portNUM_PROCESSORS == 2
+    result = result && (DPORT_REG_GET_BIT(DPORT_APP_CACHE_CTRL_REG, DPORT_APP_CACHE_ENABLE) != 0);
+#endif
+    return result;
 }