MIPS: generic: Fix KASLR for generic kernel.

MIPS: generic: Fix KASLR for generic kernel.

The KASLR code requires that the plat_get_fdt() function return the
address of the device tree, and it must be available early in the boot,
before prom_init() is called. Move the code determining the address of
the device tree into plat_get_fdt, and call that from prom_init().

The fdt pointer will be set up by plat_get_fdt() called from
relocate_kernel initially and once the relocated kernel has started,
prom_init() will use it again to determine the address in the relocated
image.

Fixes: eed0eabd12ef ("MIPS: generic: Introduce generic DT-based board support")
Signed-off-by: Matt Redfearn <[email protected]>
Reviewed-by: James Hogan <[email protected]>
Reviewed-by: Paul Burton <[email protected]>
Cc: [email protected]
Cc: [email protected]
Patchwork: https://patchwork.linux-mips.org/patch/14415/
Signed-off-by: Ralf Baechle <[email protected]>