esp32: Prefix ROM routines with `esp32_rom_`

Also provide their prototypes in `soc.h`.  This should help
readability, since some ROM functions, with their names as provided by
Espressif, have sometimes the same prefix as Zephyr APIs.

Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>
diff --git a/drivers/serial/uart_esp32.c b/drivers/serial/uart_esp32.c
index 58325a8..dd93de3 100644
--- a/drivers/serial/uart_esp32.c
+++ b/drivers/serial/uart_esp32.c
@@ -5,9 +5,9 @@
  */
 
 /* Include esp-idf headers first to avoid redefining BIT() macro */
-#include <rom/uart.h>
 #include <rom/ets_sys.h>
 
+#include <soc.h>
 #include <uart.h>
 #include <errno.h>
 
@@ -16,7 +16,7 @@
 {
 	ARG_UNUSED(dev);
 
-	uart_tx_one_char(c);
+	esp32_rom_uart_tx_one_char(c);
 
 	return c;
 }
@@ -25,7 +25,7 @@
 {
 	ARG_UNUSED(dev);
 
-	switch (uart_rx_one_char(p_char)) {
+	switch (esp32_rom_uart_rx_one_char(p_char)) {
 	case OK:
 		return 0;
 	case PENDING:
@@ -43,7 +43,7 @@
 {
 	ARG_UNUSED(dev);
 
-	uartAttach();
+	esp32_rom_uart_attach();
 
 	return 0;
 }