You got a little confused with the number of digits in the addresses I think.

In chapter 3.4 it says

H'FFFC0000..H'FFFCFFFF     SDRAM mode setting

H'FFFD0000..H'FFFCBFFF     Reserved area

H'FFFFC000..H'FFFFFFFF     On-chip peripheral IO registers

In chapter 26.1 you find registers in the range H'FFFC0000..H'FFFFFFFF, as it is also said in table 8.2.

So it uses also the reserved area for special function registers.