kconfig: Fix spelling of sym_is_changable

There is a spelling mistake in "changable", it is corrected to
"changeable" and all call sites are updated accordingly.

Signed-off-by: Marco Ammon <marco.ammon@fau.de>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index 18e8051..caab733 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -796,7 +796,7 @@ int conf_write_defconfig(const char *filename)
 				goto next_menu;
 			sym->flags &= ~SYMBOL_WRITE;
 			/* If we cannot change the symbol - skip */
-			if (!sym_is_changable(sym))
+			if (!sym_is_changeable(sym))
 				goto next_menu;
 			/* If symbol equals to default value - skip */
 			if (strcmp(sym_get_string_value(sym), sym_get_string_default(sym)) == 0)