serial: uartlite: Use dynamic allocation for major number when uart ports > 4

Device number 204 has a range of minors on major number.
uart_register_driver is failing due to lack of minor numbers
when more number of uart ports used. So, to avoid minor number
limitation on 204 major number use dynamic major allocation
when more than 4 uart ports used otherwise use static major
allocation.

https://docs.kernel.org/arch/arm/sa1100/serial_uart.html

Signed-off-by: Manikanta Guntupalli <manikanta.guntupalli@amd.com>
Link: https://lore.kernel.org/r/20231116134003.3762725-3-manikanta.guntupalli@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/Kconfig

@@ -532,6 +532,9 @@ config SERIAL_UARTLITE_NR_UARTS
 	help
 	  Set this to the number of uartlites in your system, or the number
 	  you think you might implement.
+	  If maximum number of uartlite serial ports is more than 4, then the
+	  driver uses dynamic allocation instead of static allocation for major
+	  number.
 
 config SERIAL_SUNCORE
 	bool

drivers/tty/serial/uartlite.c

@@ -24,8 +24,13 @@
 #include <linux/pm_runtime.h>
 
 #define ULITE_NAME		"ttyUL"
+#if CONFIG_SERIAL_UARTLITE_NR_UARTS > 4
+#define ULITE_MAJOR             0       /* use dynamic node allocation */
+#define ULITE_MINOR             0
+#else
 #define ULITE_MAJOR		204
 #define ULITE_MINOR		187
+#endif
 #define ULITE_NR_UARTS		CONFIG_SERIAL_UARTLITE_NR_UARTS
 
 /* ---------------------------------------------------------------------