uart: fix misleading files for UART2

Includes: header files, ld files and clk.c

ESP32-C3 only have UART0 and UART1.

components/esp32c3/ld/esp32c3.peripherals.ld

@@ -1,6 +1,5 @@
 PROVIDE ( UART0 = 0x60000000 );
 PROVIDE ( UART1 = 0x60010000 );
-PROVIDE ( UART2 = 0x6002e000 );
 PROVIDE ( SPIMEM1 = 0x60002000 );
 PROVIDE ( SPIMEM0 = 0x60003000 );
 PROVIDE ( GPIO = 0x60004000 );