rpmsg: set ept address to incease num when alloc from the bitmap

[GUIDINGLI]

rpmsg: set ept address to incease num when alloc from the bitmap

CPU0                                CPU1
create_ept1:addr1                   create_ept1
OK                       <======    msg1
OK                       <======    msg2
OK                       <======    msg3
                           msg4
                         <======    msg4 on the virtioqueue
close_ept1                          close_ept1

create_ept2:addr1                   create_ept1
(same addr with ept1)
                           msg4
ept2 recv ept1 msg ERROR <======

The msg4 which belong to ep1, error received by ept2.

For the issue, I give a resolve method,
for the rpmsg_get_address(), always return a new increased num.

This should compile with OpenAMP/libmetal#263

[arnopo]

The issue is well described in the commit message.
Could you also explain in the commit message the solution implemented?

[GUIDINGLI]

The issue is well described in the commit message. Could you also explain in the commit message the solution implemented?

@arnopo
Commit message updated, please review

[xiaoxiang781216]

LGTM.