ci: split xtensa jobs into three separate jobs (instead of two)

This is necessary because new defconfig were recently added to
Xtensa-based Espressif SoCs and the build job may exceed 2 hours.
In order to avoid increasing job timeout, a specific job for each
supported SoC (ESP32, ESP32-S2 and ESP32-S3) was created instead.

Signed-off-by: Tiago Medicci <tiago.medicci@espressif.com>

.github/workflows/arch.yml

@@ -230,7 +230,7 @@ jobs:
                 skip_build=1
               fi
   
-            # For "Arch / Board: xtensa": Build xtensa-01, xtensa-02
+            # For "Arch / Board: xtensa": Build xtensa-01, xtensa-02, xtensa-03
             elif [[ "$arch_contains_xtensa" == "1" || "$board_contains_xtensa" == "1" ]]; then
               if [[ "$board" != *"xtensa-"* ]]; then
                 skip_build=1

.github/workflows/build.yml

@@ -121,7 +121,7 @@ jobs:
         [
           "arm-01", "risc-v-01", "sim-01", "xtensa-01", "arm64-01", "x86_64-01", "other",
           "arm-02", "risc-v-02", "sim-02", "xtensa-02",
-          "arm-03", "risc-v-03", "sim-03",
+          "arm-03", "risc-v-03", "sim-03", "xtensa-03",
           "arm-04", "risc-v-04",
           "arm-05", "risc-v-05",
           "arm-06", "risc-v-06",