mm: remove CONFIG_TRANSPARENT_HUGE_PAGECACHE

Commit e496cf3d ("thp: introduce CONFIG_TRANSPARENT_HUGE_PAGECACHE")
notes that it should be reverted when the PowerPC problem was fixed.  The
commit fixing the PowerPC problem (953c66c2) did not revert the
commit; instead setting CONFIG_TRANSPARENT_HUGE_PAGECACHE to the same as
CONFIG_TRANSPARENT_HUGEPAGE.  Checking with Kirill and Aneesh, this was an
oversight, so remove the Kconfig symbol and undo the work of commit
e496cf3d.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Link: http://lkml.kernel.org/r/20200318140253.6141-6-willy@infradead.org


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>