Enable nocache sections using the linker. PP5022/4 must use SW_CORELOCK now with...

Enable nocache sections using the linker. PP5022/4 must use SW_CORELOCK now with shared variables in DRAM (it seems swp(b) is at least partially broken on all PP or I'm doing something very wrong here :\). For core-shared data use SHAREDBSS/DATA_ATTR. NOCACHEBSS/DATA_ATTR is available whether or not single core is forced for static peripheral-DMA buffer allocation without use of the UNCACHED_ADDR macro in code and is likely useful on a non-PP target with a data cache (although not actually enabled in config.h and the .lds's in this commit).

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@16981 a1c6a512-1295-4272-9138-f99709370657