RISC-V: Move from EARLY_PRINTK to SBI earlycon

Now that we have earlycon support in the SBI console driver there is no
reason to have our arch-specific early printk support.  This patch set
turns on SBI earlycon support and removes the old early printk.

arch/riscv/Kconfig.debug

-config EARLY_PRINTK
-	def_bool y

arch/riscv/configs/defconfig

@@ -46,6 +46,7 @@ CONFIG_INPUT_MOUSEDEV=y
 CONFIG_SERIAL_8250=y
 CONFIG_SERIAL_8250_CONSOLE=y
 CONFIG_SERIAL_OF_PLATFORM=y
+CONFIG_SERIAL_EARLYCON_RISCV_SBI=y
 CONFIG_HVC_RISCV_SBI=y
 # CONFIG_PTP_1588_CLOCK is not set
 CONFIG_DRM=y

arch/riscv/kernel/setup.c

@@ -35,31 +35,9 @@
 #include <asm/sections.h>
 #include <asm/pgtable.h>
 #include <asm/smp.h>
-#include <asm/sbi.h>
 #include <asm/tlbflush.h>
 #include <asm/thread_info.h>
 
-#ifdef CONFIG_EARLY_PRINTK
-static void sbi_console_write(struct console *co, const char *buf,
-			      unsigned int n)
-{
-	int i;
-
-	for (i = 0; i < n; ++i) {
-		if (buf[i] == '\n')
-			sbi_console_putchar('\r');
-		sbi_console_putchar(buf[i]);
-	}
-}
-
-struct console riscv_sbi_early_console_dev __initdata = {
-	.name	= "early",
-	.write	= sbi_console_write,
-	.flags	= CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
-	.index	= -1
-};
-#endif
-
 #ifdef CONFIG_DUMMY_CONSOLE
 struct screen_info screen_info = {
 	.orig_video_lines	= 30,
@@ -219,12 +197,6 @@ static void __init setup_bootmem(void)
 
 void __init setup_arch(char **cmdline_p)
 {
-#if defined(CONFIG_EARLY_PRINTK)
-       if (likely(early_console == NULL)) {
-               early_console = &riscv_sbi_early_console_dev;
-               register_console(early_console);
-       }
-#endif
 	*cmdline_p = boot_command_line;
 
 	parse_early_param();