ice: fix and consolidate logging of NVM/firmware version information

Logging the firmware/NVM information during driver load is redundant since
that information is also available via ethtool.  Move the functionality
found in ice_nvm_version_str() directly into ice_get_drvinfo() and remove
calling the former and logging that info during driver probe.  This also
gets rid of a bug in ice_nvm_version_str() where it returns a pointer to
a buffer which is free'ed when that function exits.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>