Gigabeat S: Switch SSI1 and 2 around so that playback can use the shared peripheral...

Gigabeat S: Switch SSI1 and 2 around so that playback can use the shared peripheral DMA with SSI2 which doesn't require use of the peripheral DMA unit-- SSI2 is mapped to the SDMA core address space. Fix some break keywords in get_script_pc(). Use the patched script for mcu_2_app (BSP appears to have neglected to update that). Use _SHP instead of _SP for shared peripheral constants (consistency).

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@20254 a1c6a512-1295-4272-9138-f99709370657