[patch 1/3] FS_MBCACHE: don't needlessly make it built-in

Assume you have:
- one or more of ext2/3/4 statically built into your kernel
- none of these with extended attributes enabled and
- want to add onother one of ext2/3/4 modular and with
extended attributes enabled

then you currently have to reboot to use it since this results in
CONFIG_FS_MBCACHE=y.

That's not a common issue, but I just ran into it and since there's no
reason to get a built-in mbcache in this case this patch fixes it.

Signed-off-by: Adrian Bunk <[e-mail]>
Cc: Andreas Gruenbacher <[e-mail]>
Cc: Al Viro <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

fs/Kconfig

···
 config FS_MBCACHE
 # Meta block cache for Extended Attributes (ext2/ext3/ext4)
 	tristate
-	depends on EXT2_FS_XATTR || EXT3_FS_XATTR || EXT4_FS_XATTR
-	default y if EXT2_FS=y || EXT3_FS=y || EXT4_FS=y
-	default m if EXT2_FS=m || EXT3_FS=m || EXT4_FS=m
+	default y if EXT2_FS=y && EXT2_FS_XATTR
+	default y if EXT3_FS=y && EXT3_FS_XATTR
+	default y if EXT4_FS=y && EXT4_FS_XATTR
+	default m if EXT2_FS_XATTR || EXT3_FS_XATTR || EXT4_FS_XATTR
 
 config REISERFS_FS
 	tristate "Reiserfs support"