Just fallback on the default of 12 like other architectures. This
allows changing the system-mode-affecting definition of
TARGET_PAGE_BITS without affecting microblaze linux-user.
Signed-off-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>