kbuild: drop $(version_h) from MRPROPER_FILES

Now $(version_h) is include/generated/uapi/linux/version.h.

$(version_h) in MRPROPER_FILES is redundant because it is covered
by include/generated in MRPROPER_DIRS.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>

Makefile

@@ -1171,7 +1171,7 @@ CLEAN_DIRS  += $(MODVERDIR)
 # Directories & files removed with 'make mrproper'
 MRPROPER_DIRS  += include/config usr/include include/generated          \
 		  arch/*/include/generated .tmp_objdiff
-MRPROPER_FILES += .config .config.old .version .old_version $(version_h) \
+MRPROPER_FILES += .config .config.old .version .old_version \
 		  Module.symvers tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS \
 		  signing_key.priv signing_key.x509 x509.genkey		\
 		  extra_certificates signing_key.x509.keyid		\