powerpc: mpc85xx: Drop u-boot-with-spl.bin on selected boards

powerpc: mpc85xx: Drop u-boot-with-spl.bin on selected boards

For SoCs with PBL, u-boot-with-spl-pbl.bin is the final image for
SPL boot. Drop unused u-boot-with-spl.bin.

Signed-off-by: York Sun <[email protected]>
CC: Ashish Kumar <[email protected]>
CC: Ruchika Gupta <[email protected]>
CC: Priyanka Jain <[email protected]>
CC: Shengzhou Liu <[email protected]>