misc: fastrpc: Mark all sessions as invalid in cb_remove

misc: fastrpc: Mark all sessions as invalid in cb_remove

In remoteproc shutdown sequence, rpmsg_remove will get called which
would depopulate all the child nodes that have been created during
rpmsg_probe. This would result in cb_remove call for all the context
banks for the remoteproc. In cb_remove function, session 0 is
getting skipped which is not correct as session 0 will never become
available again. Add changes to mark session 0 also as invalid.

Fixes: f6f9279f2bf0 ("misc: fastrpc: Add Qualcomm fastrpc basic driver model")
Cc: stable <stable@kernel.org>
Signed-off-by: Ekansh Gupta <quic_ekangupt@quicinc.com>
Link: https://lore.kernel.org/r/20240108114833.20480-1-quic_ekangupt@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>