Fix MTRR compat ioctl

Fix MTRR compat ioctl

The MTRR compat code wasn't calling the lowlevel MTRR setup due to a switch
block not handling the compat case.

Before:
(WW) I810(0): Failed to set up write-combining range (0xd0000000,0x10000000)

After:
reg00: base=0x00000000 (   0MB), size=1024MB: write-back, count=1
reg01: base=0x40000000 (1024MB), size= 512MB: write-back, count=1
reg02: base=0x5f700000 (1527MB), size=   1MB: uncachable, count=1
reg03: base=0x5f800000 (1528MB), size=   8MB: uncachable, count=1
reg04: base=0xd0000000 (3328MB), size= 256MB: write-combining, count=1

Signed-off-by: Zwane Mwaikambo <zwane@infradead.org>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>