feat(esp_riscv_trace): add ESP32-S31 support

ESP32-S31 uses the same trace encoder IP as ESP32-P4. Of the E-Trace v2.0
parameters the two targets report, only privilege_width_p differs (1 on P4,
2 on S31), and it affects both the sync packet layout and the filter's
privilege selector.

- Add the SOC_RISCV_TRACE_* caps for ESP32-S31 along with the esp32s31 LL, and
  declare TRACE0/TRACE1 in the target's trace_struct.h.
- Carry privilege_width_p as SOC_RISCV_TRACE_PRIV_WIDTH so the sync packet
  decoder can locate the address field, which starts one bit later on targets
  that implement supervisor mode.
- Use the RISC-V architectural privilege encoding (0 user, 1 supervisor,
  3 machine) in the public filter enum so the values do not change per target,
  and let each LL narrow them to its own register field.
- Add riscv_trace_ll_priv_is_supported() per target, so a privilege level the
  selector cannot represent is rejected with ESP_ERR_NOT_SUPPORTED rather than
  being silently narrowed to a different level. It lives next to the narrowing
  code so the two cannot drift apart.
- Fix trace buffer allocation on targets whose internal RAM is not reached
  through a cache. esp_cache_get_alignment() reports 0 there, which underflowed
  the size check and failed every allocation. Align base and size to the larger
  of the reported cache line and the encoder's 4-byte write granularity.

components/soc/esp32p4/include/soc/Kconfig.soc_caps.in

@@ -1950,3 +1950,7 @@ config SOC_RISCV_TRACE_AHB_CONFIGURABLE
 config SOC_RISCV_TRACE_FILTER_SUPPORTED
     bool
     default y
+
+config SOC_RISCV_TRACE_PRIV_WIDTH
+    int
+    default 1

components/soc/esp32p4/include/soc/soc_caps.h

@@ -746,3 +746,4 @@
 #define SOC_RISCV_TRACE_HAS_CONFIG_REG              (1) /*!< Has the encoder config register */
 #define SOC_RISCV_TRACE_AHB_CONFIGURABLE            (1) /*!< AHB write master is configurable */
 #define SOC_RISCV_TRACE_FILTER_SUPPORTED            (1) /*!< Has the filter unit */
+#define SOC_RISCV_TRACE_PRIV_WIDTH                  (1U) /*!< Bits in the privilege field (privilege_width_p) */