api: shm: add flags to shm_reserve and function to find external mem
api: shm: add flags to shm_reserve and function to find external mem

The ODP_SHM_SINGLE_VA flag is created: when set (at odp_shm_reserve()),
this flag guarantees that all ODP threads sharing this memory
block will see the block at the same address (regadless of ODP
thread type -pthread vs process- or fork time)

The flag ODP_SHM_EXPORT is added: when passed at odp_shm_reserve() time
the memory block becomes visible to other ODP instances.
The function odp_shm_import() is added: this function enables to
reserve block of memories exported by other ODP instances (using the
ODP_SHM_EXPORT flag).

Signed-off-by: Christophe Milard <99616a981fa4477cda708a70f78076761c0c9f1c@linaro.org>
Reviewed-and-tested-by: Bill Fischofer <52f3c909d51cc5d355a68a403df6906b3c1a8f83@linaro.org>
Reviewed-by: Petri Savolainen <d528fd253b9aaf78fa72edbcc6249e82047f6ce6@nokia.com>
Signed-off-by: Maxim Uvarov <db4d16e02ae2d7493db430203537da8b2e34f290@linaro.org>

erachmi/odp,erachmi/odp,erachmi/odp,erachmi/odp