softmmu/physmem: Mark shared anonymous memory RAM_SHARED

softmmu/physmem: Mark shared anonymous memory RAM_SHARED

Let's drop the "shared" parameter from ram_block_add() and properly
store it in the flags of the ram block instead, such that
qemu_ram_is_shared() properly succeeds on all ram blocks that were mapped
MAP_SHARED.

We'll use this information next to fix some cases with shared anonymous
memory.

Reviewed-by: Igor Kotrasinski <[email protected]>
Reviewed-by: Richard Henderson <[email protected]>
Reviewed-by: Peter Xu <[email protected]>
Signed-off-by: David Hildenbrand <[email protected]>
Message-Id: <20210406080126[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>