iwlwifi: yoyo: cleanup internal buffer allocation in D3

With recent changes in the firmware SRAM debug during D3 is
enabled by default and need not be enabled by driver.
cleaning the code to align the same.

Signed-off-by: Mukesh Sisodiya <mukesh.sisodiya@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210802215208.8535203d0ef7.Ib1695ce5de921b0472d0b1052e729e071573b863@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>