powerpc/mm: Cleanup LPCR defines

This makes it easy to verify we are not overloading the bits.
No functionality change by this patch.

mpe: Cleanup more. Completely fixup whitespace, convert all UL values to
ASM_CONST(), and replace all occurrences of 63-x with the actual shift.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>