m68k: Kconfig.debug: Replace single quotes

Replace single quotes in strings with double quotes to match the majority
of the rest of the kernel's Kconfig files.
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Link: https://lore.kernel.org/r/20220524075848.21684-3-juergh@canonical.comSigned-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

arch/m68k/Kconfig.debug

 # SPDX-License-Identifier: GPL-2.0
 
 config BOOTPARAM
-	bool 'Compiled-in Kernel Boot Parameter'
+	bool "Compiled-in Kernel Boot Parameter"
 
 config BOOTPARAM_STRING
-	string 'Kernel Boot Parameter'
-	default 'console=ttyS0,19200'
+	string "Kernel Boot Parameter"
+	default "console=ttyS0,19200"
 	depends on BOOTPARAM
 
 config EARLY_PRINTK