dma-buf: move system_cc_shared heap under separate Kconfig

dma-buf: move system_cc_shared heap under separate Kconfig

While system heap and system_cc_shared heap share a lot of code
and hence the same source file, their users have different needs.

system heap users need it to be a loadable module, while
system_cc_shared heap users don't.

Building as a loadable module breaks system_cc_shared heap on
powerpc and s390 due to un-exported set_memory_encrypted /
set_memory_decrypted functions.

Fix these by reorganising code to put the system_cc_shared heap
under a new Kconfig symbol, which allows either building both
into the kernel, or leave encryption up to the consumers of the
system heap.

Fixes: fd55edff8a0a ("dma-buf: heaps: system: Turn the heap into a module")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
  [sumits: updated DMABUF_HEAPS_CC_SYSTEM to DMABUF_HEAPS_SYSTEM_CC_SHARED]
Reviewed-by: T.J. Mercier <tjmercier@google.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://patch.msgid.link/20260610142329.3836808-1-sumit.semwal@linaro.org