mm: cma: don't replace lowmem pages with highmem

    The filesystem layer expects pages in the block device's mapping to not
    be in highmem (the mapping's gfp mask is set in bdget()), but CMA can
    currently replace lowmem pages with highmem pages, leading to crashes in
    filesystem code such as the one below:

      Unable to handle kernel NULL pointer dereference at virtual address 00000400
      pgd = c0c98000
      [00000400] *pgd=00c91831, *pte=00000000, *ppte=00000000
      Internal error: Oops: 817 [#1] PREEMPT SMP ARM
      CPU: 0    Not tainted  (3.5.0-rc5+ #80)
      PC is at __memzero+0x24/0x80
      ...
      Process fsstress (pid: 323, stack limit = 0xc0cbc2f0)
      Backtrace:
      [<c010e3f0>] (ext4_getblk+0x0/0x180) from [<c010e58c>] (ext4_bread+0x1c/0x98)
      [<c010e570>] (ext4_bread+0x0/0x98) from [<c0117944>] (ext4_mkdir+0x160/0x3bc)
       r4:c15337f0
      [<c01177e4>] (ext4_mkdir+0x0/0x3bc) from [<c00c29e0>] (vfs_mkdir+0x8c/0x98)
      [<c00c2954>] (vfs_mkdir+0x0/0x98) from [<c00c2a60>] (sys_mkdirat+0x74/0xac)
       r6:00000000 r5:c152eb40 r4:000001ff r3:c14b43f0
      [<c00c29ec>] (sys_mkdirat+0x0/0xac) from [<c00c2ab8>] (sys_mkdir+0x20/0x24)
       r6:beccdcf0 r5:00074000 r4:beccdbbc
      [<c00c2a98>] (sys_mkdir+0x0/0x24) from [<c000e3c0>] (ret_fast_syscall+0x0/0x30)

    Fix this by replacing only highmem pages with highmem.
Revert "mach-msm: Introduce Dynamic hotplug driver for mako"

This reverts commit 80556f9d36835d00395b786b150c863c48671db2.