lib: cleanup "fake" tristates in Kconfig

These 7 DECOMPRESS_ options (e.g.  DECOMPRESS_GZIP) currently have the
tristate type, but can never be set to M.  Their only valid values are Y
and N, making them effectively booleans.

Let's make their types more accurate by changing them to 'bool'.  Note
that this is only a code cleanup, there is no functional change.

These bistates were found by kconfirm, a static analysis tool for Kconfig.

Link: https://lore.kernel.org/20260817210311.2142999-1-julianbraha@gmail.com
Signed-off-by: Julian Braha <julianbraha@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Julia Lawall <julia.lawall@inria.fr>

lib/Kconfig

@@ -219,29 +219,29 @@ source "lib/xz/Kconfig"
 #
 config DECOMPRESS_GZIP
 	select ZLIB_INFLATE
-	tristate
+	bool
 
 config DECOMPRESS_BZIP2
-	tristate
+	bool
 
 config DECOMPRESS_LZMA
-	tristate
+	bool
 
 config DECOMPRESS_XZ
 	select XZ_DEC
-	tristate
+	bool
 
 config DECOMPRESS_LZO
 	select LZO_DECOMPRESS
-	tristate
+	bool
 
 config DECOMPRESS_LZ4
 	select LZ4_DECOMPRESS
-	tristate
+	bool
 
 config DECOMPRESS_ZSTD
 	select ZSTD_DECOMPRESS
-	tristate
+	bool
 
 #
 # Generic allocator support is selected if needed