powerpc: mpc85xx: Fix CONFIG_OF_SEPARATE support for NOR booting

powerpc: mpc85xx: Fix CONFIG_OF_SEPARATE support for NOR booting

Commit b0cae0c38545 ("powerpc: mpc85xx: Fix CONFIG_OF_SEPARATE support")
fixed SD card booting on mpc85xx boards but broke NOR booting on these
boards. Reason is that U-Boot build system for NOR images uses binman and
this binman ignores alignment defined in linker script. Instead it has own
config file where is alignment defined.

Fix binman alignment for mpc85xx boards to match what is _now_ defined in
linker script.

This change fixes building of U-Boot for NOR booting on P2020 board.

Fixes: b0cae0c38545 ("powerpc: mpc85xx: Fix CONFIG_OF_SEPARATE support")
Signed-off-by: Pali Rohár <pali@kernel.org>