powerpc/8xx: Use a larger CPM1 command check mask

The CPM1 command mask is defined for use with the standard
CPM1 command register as described in the user's manual:
  0  |1        3|4    7|8   11|12      14| 15|
  RST|    -     |OPCODE|CH_NUM|     -    |FLG|

In the QMC extension the CPM1 command register is redefined
(QMC supplement user's manuel) with the following mapping:
  0  |1        3|4    7|8           13|14| 15|
  RST|QMC OPCODE|  1110|CHANNEL_NUMBER| -|FLG|

Extend the check command mask in order to support both the
standard CH_NUM field and the QMC extension CHANNEL_NUMBER
field.

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Acked-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230217145645.1768659-5-herve.codina@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>