serial: s5p: Add Apple M1 support

Apple M1 SoCs include an S5L UART which is a variant of the S5P
UART.  Add support for this variant and enable it by default
on Apple SoCs.

Signed-off-by: Mark Kettenis <kettenis@openbsd.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/include/asm/arch-m1/uart.h b/arch/arm/include/asm/arch-m1/uart.h
new file mode 100644
index 0000000..d2a17a2
--- /dev/null
+++ b/arch/arm/include/asm/arch-m1/uart.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * (C) Copyright 2009 Samsung Electronics
+ * Minkyu Kang <mk7.kang@samsung.com>
+ * Heungjun Kim <riverful.kim@samsung.com>
+ */
+
+#ifndef __ASM_ARCH_UART_H_
+#define __ASM_ARCH_UART_H_
+
+#ifndef __ASSEMBLY__
+/* baudrate rest value */
+union br_rest {
+	unsigned short	slot;		/* udivslot */
+	unsigned char	value;		/* ufracval */
+};
+
+struct s5p_uart {
+	unsigned int	ulcon;
+	unsigned int	ucon;
+	unsigned int	ufcon;
+	unsigned int	umcon;
+	unsigned int	utrstat;
+	unsigned int	uerstat;
+	unsigned int	ufstat;
+	unsigned int	umstat;
+	unsigned int	utxh;
+	unsigned int	urxh;
+	unsigned int	ubrdiv;
+	union br_rest	rest;
+	unsigned char	res3[0x3fd0];
+};
+
+static inline int s5p_uart_divslot(void)
+{
+	return 0;
+}
+
+#endif	/* __ASSEMBLY__ */
+
+#endif