Report from Sparse:

target-moxie/mmu.h:9:12: error: dubious one-bit signed bitfield
target-moxie/mmu.h:10:12: error: dubious one-bit signed bitfield
target-moxie/mmu.h:11:12: error: dubious one-bit signed bitfield
target-moxie/mmu.h:12:12: error: dubious one-bit signed bitfield
target-moxie/mmu.h:13:12: error: dubious one-bit signed bitfield

Cc: Anthony Green <green@moxielogic.com>
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>