NIOS2: fix kconfig unmet dependency warning for SERIAL_CORE_CONSOLE

SERIAL_CORE_CONSOLE depends on TTY so EARLY_PRINTK should also
depend on TTY so that it does not select SERIAL_CORE_CONSOLE
inadvertently.

WARNING: unmet direct dependencies detected for SERIAL_CORE_CONSOLE
  Depends on [n]: TTY [=n] && HAS_IOMEM [=y]
  Selected by [y]:
  - EARLY_PRINTK [=y]

Fixes: e8bf5bc7 ("nios2: add early printk support")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>

arch/nios2/Kconfig.debug

@@ -3,9 +3,10 @@
 config EARLY_PRINTK
 	bool "Activate early kernel debugging"
 	default y
+	depends on TTY
 	select SERIAL_CORE_CONSOLE
 	help
-	  Enable early printk on console
+	  Enable early printk on console.
 	  This is useful for kernel debugging when your machine crashes very
 	  early before the console code is initialized.
 	  You should normally say N here, unless you want to debug such a crash.