i40e: refactor AQ CMD buffer debug printing

This patch refactors the '%*ph' printk format specifier to instead use
the print_hex_dump function, as recommended by the '%*ph' documentation.
This produces better/more standardized output.

Change-ID: Id56700b4e8abc40ff8c04bc8379e7df04cb4d6fd
Signed-off-by: Alan Brady <alan.brady@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>