mm: drop redundant ARCH_ENABLE_SPLIT_PMD_PTLOCK

mm: drop redundant ARCH_ENABLE_SPLIT_PMD_PTLOCK

ARCH_ENABLE_SPLIT_PMD_PTLOCKS has duplicate definitions on platforms
that subscribe it.  Drop these redundant definitions and instead just
select it on applicable platforms.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Anshuman Khandual <[email protected]>
Acked-by: Catalin Marinas <[email protected]>	[arm64]
Acked-by: Heiko Carstens <[email protected]>		[s390]
Cc: Will Deacon <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Yoshinori Sato <[email protected]>
Cc: Rich Felker <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Helge Deller <[email protected]>
Cc: "James E.J. Bottomley" <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Russell King <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Vineet Gupta <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>