iwlwifi: mvm: don't collect logs in the interrupt thread

Instead of reading all the data in the context of the
interrupt thread, collect the data in the restart flow
before the actual restart takes place so that the device
still has all the information.
Remove iwl_mvm_fw_error_sram_dump and move its content to
iwl_mvm_fw_error_dump.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>