fix(esp_hw_support): use elif __riscv guard in spinlock.h

spinlock.h used #else to include riscv/rv_utils.h for all non-Xtensa
targets. On Linux host (neither __XTENSA__ nor __riscv defined), this
pulls in a non-existent header. Change to #elif __riscv, matching
esp_cpu.h's existing pattern.

components/esp_hw_support/include/spinlock.h

@@ -13,7 +13,7 @@
 #if __XTENSA__
 #include "xtensa/xtruntime.h"
 #include "xt_utils.h"
-#else
+#elif __riscv
 #include "riscv/rv_utils.h"
 #endif