populate_sdk_base: Put populate_sdk under sstate control

populate_sdk_base: Put populate_sdk under sstate control

Adding populate_sdk task to SSTATE_TASKS should make sstate machinery
to generate manifest for deployed sdk artifacts and do final deployment
to SDK_DEPLOY.

Set stamp-extra-info flag for do_populate_sdk task. This flag is used
in the name of sstate manifest. Setting it to predetermined value for
populate_sdk task should help to get correct manifest filenames when
processing runQueueTask events.

The do_populate_sdk function is also executed by do_populate_sdk_ext
so in order to avoid conflicts with the sstate postfuncs, split
the main code into a separate function.

We also need to set SDKDEPLOYDIR as do_populate_sdk_ext expects
it in order not to break ESDK generation.

(From OE-Core rev: 8361376b8ef0147276c9ee31349e904d86900593)

Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>