soc: fsl: cpm1: qmc: Fix __iomem addresses declaration

Running sparse (make C=1) on qmc.c raises a lot of warning such as:
  ...
  warning: incorrect type in assignment (different address spaces)
     expected struct cpm_buf_desc [usertype] *[noderef] __iomem bd
     got struct cpm_buf_desc [noderef] [usertype] __iomem *txbd_free
  ...

Indeed, some variable were declared 'type *__iomem var' instead of
'type __iomem *var'.

Use the correct declaration to remove these warnings.

Fixes: 3178d58e ("soc: fsl: cpm1: Add support for QMC")
Cc: stable@vger.kernel.org
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/20231205152116.122512-3-herve.codina@bootlin.com