[chip dv] Get ALL UART tests working

Write extra vseq for smoke test that facilitates the UART0 connection.

Refactor the tx rx vseq to reuse some other refactored code in its base
classes.

Tests passing with these changes:
- chip_sw_uart_smoketest
- chip_sw_uart_smoketest_signed
- chip_sw_uart_tx_rx
- chip_sw_uart_tx_rx_idx1
- chip_sw_uart_tx_rx_idx2
- chip_sw_uart_tx_rx_idx3

Tests that need to be debugged:
- chip_sw_uart_tx_rx_alt_clk_freq
- chip_sw_uart_tx_rx_alt_clk_freq_low_speed

Tests failing from before:
- chip_sw_uart_tx_rx_bootstrap

Signed-off-by: Srikrishna Iyer <sriyer@google.com>
diff --git a/hw/top_earlgrey/dv/chip_smoketests.hjson b/hw/top_earlgrey/dv/chip_smoketests.hjson
index 327a335..da11453 100644
--- a/hw/top_earlgrey/dv/chip_smoketests.hjson
+++ b/hw/top_earlgrey/dv/chip_smoketests.hjson
@@ -108,7 +108,7 @@
     }
     {
       name: chip_sw_uart_smoketest
-      uvm_test_seq: chip_sw_base_vseq
+      uvm_test_seq: chip_sw_uart_smoke_vseq
       sw_images: ["//sw/device/tests:uart_smoketest:1"]
       en_run_modes: ["sw_test_mode_test_rom"]
     }