misc: make mapped areas in tcsm driver non-cacheable in the normal way
misc: rename jz_tcsm_70later to jz_vpu

Changes name (but not yet interface) to that in the NPM801 kernel.
This will simplify porting over XBOMX a bit.
Also clarify Kconfig description and name.
misc: jz_vpu: remove unused structure
gcw0_defconfig: Make JZ_VPU default with this branch