aspeed/ast2600: Fix SPL linker script

The commit 99e2fbcb ("linker_lists: Rename sections to remove .
prefix") changed the name of the linker list sections. As the Aspeed SPL
linker wasn't in the tree yet, it missed the change.

This updates the SPL linker to match arch/arm/cpu/u-boot-spl.lds which
Aspeed was copied from.

Fixes: 442a69c1 ("configs: ast2600: Move SPL bss section to DRAM space")
Signed-off-by: Joel Stanley <joel@jms.id.au>