serial: max310x: Driver rework

This patch rework max310x driver.
Major changes have been made:
- Prepare driver to support ICs with more than one UART.
- Prepare driver to support work with I2C-bus.
The patch changes almost every function and can not be divided into parts.

Signed-off-by: Alexander Shiyan <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: shcgit

drivers/tty/serial/Kconfig

@@ -291,9 +291,9 @@ config SERIAL_MAX3100
 
 config SERIAL_MAX310X
 	bool "MAX310X support"
-	depends on SPI
+	depends on SPI_MASTER
 	select SERIAL_CORE
-	select REGMAP_SPI if SPI
+	select REGMAP_SPI if SPI_MASTER
 	default n
 	help
 	  This selects support for an advanced UART from Maxim (Dallas).