hw/xtensa: add ESP32 machine

Author: igrr

configs/devices/xtensa-softmmu/default.mak

@@ -7,3 +7,4 @@ CONFIG_SEMIHOSTING=y
 CONFIG_XTENSA_SIM=y
 CONFIG_XTENSA_VIRT=y
 CONFIG_XTENSA_XTFPGA=y
+CONFIG_XTENSA_ESP32=y

hw/xtensa/Kconfig

@@ -12,3 +12,14 @@ config XTENSA_XTFPGA
     select OPENCORES_ETH
     select PFLASH_CFI01
     select SERIAL
+
+config XTENSA_ESP32
+    bool
+    select SSI
+    select SSI_M25P80
+    select UNIMP
+    select OPENCORES_ETH
+    select DWC_SDMMC
+    select TMP105
+
+