stmmac_reinit_queues() fails to fix up the RX hash.  Even if the number
of channels gets restricted, the output of `ethtool -x' indicates that
all RX queues are used:

  $ ethtool -l enp0s29f2
  Channel parameters for enp0s29f2:
  Pre-set maximums:
  RX:		8
  TX:		8
  Other:		n/a
  Combined:	n/a
  Current hardware settings:
  RX:		8
  TX:		8
  Other:		n/a
  Combined:	n/a
  $ ethtool -x enp0s29f2
  RX flow hash indirection table for enp0s29f2 with 8 RX ring(s):
      0:      0     1     2     3     4     5     6     7
      8:      0     1     2     3     4     5     6     7
  [...]
  $ ethtool -L enp0s29f2 rx 3
  $ ethtool -x enp0s29f2
  RX flow hash indirection table for enp0s29f2 with 3 RX ring(s):
      0:      0     1     2     3     4     5     6     7
      8:      0     1     2     3     4     5     6     7
  [...]

Fix this by setting the indirection table according to the number
of specified queues.  The result is now as expected:

  $ ethtool -L enp0s29f2 rx 3
  $ ethtool -x enp0s29f2
  RX flow hash indirection table for enp0s29f2 with 3 RX ring(s):
      0:      0     1     2     0     1     2     0     1
      8:      2     0     1     2     0     1     2     0
  [...]

Tested on Intel Elkhart Lake.

Fixes: 0366f7e0 ("net: stmmac: add ethtool support for get/set channels")
Signed-off-by: Corinna Vinschen <vinschen@redhat.com>
Link: https://lore.kernel.org/r/20230403121120.489138-1-vinschen@redhat.comSigned-off-by: Paolo Abeni <pabeni@redhat.com>