microblaze: don't treat zero reserved memory regions as error

Before commit 721f4a65 ("mm/memblock: remove empty dummy entry") the
check for non-zero of memblock.reserved.cnt in mmu_init() would always
be true either because  memblock.reserved.cnt is initialized to 1 or
because there were memory reservations earlier.

The removal of dummy empty entry in memblock caused this check to fail
because now memblock.reserved.cnt is initialized to 0.

Remove the check for non-zero of memblock.reserved.cnt because it's
perfectly fine to have an empty memblock.reserved array that early in
boot.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Mike Rapoport <rppt@kernel.org>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20240729053327.4091459-1-rppt@kernel.org


Signed-off-by: Guenter Roeck <linux@roeck-us.net>