feat: add I2S support with formal verification and testbench

- Updated filelist to include I2S related files.
- Enhanced formal file generation script to support I2S target.
- Introduced I2S formal design and properties for verification.
- Modified formal makefile to include I2S targets and source files.
- Added I2S related source files to software build.
- Updated style audit to include I2S files.
- Implemented I2S helper functions in C tests.
- Created I2S testbench for RTL simulation.
- Added regression test for I2S controller functionality.

scripts/run_c_tests.py

@@ -26,6 +26,7 @@ TEST_SOURCES = (
     "crt/src/hal/uart_math.c",
     "crt/src/hal/timer_math.c",
     "crt/src/hal/psram_math.c",
+    "crt/src/hal/i2s_math.c",
     "crt/src/hal/sysctrl.c",
     "rtl/managed/clusterip/ps2/sw/src/ps2.c",
     "rtl/managed/clusterip/ps2/sw/src/ps2_keyboard.c",