intel: fix string truncation warnings

Fix -Wformat-truncated warnings to complete the intel directories' W=1
clean efforts. The W=1 recently got enhanced with a few new flags and
this brought up some new warnings.

Switch to using kasprintf() when possible so we always allocate the
right length strings.

summary of warnings:
drivers/net/ethernet/intel/iavf/iavf_virtchnl.c:1425:60: warning: ‘%s’ directive output may be truncated writing 4 bytes into a region of size between 1 and 11 [-Wformat-truncation=]
drivers/net/ethernet/intel/iavf/iavf_virtchnl.c:1425:17: note: ‘snprintf’ output between 7 and 17 bytes into a destination of size 13
drivers/net/ethernet/intel/ice/ice_ptp.c:43:27: warning: ‘%s’ directive output may be truncated writing up to 479 bytes into a region of size 64 [-Wformat-truncation=]
drivers/net/ethernet/intel/ice/ice_ptp.c:42:17: note: ‘snprintf’ output between 1 and 480 bytes into a destination of size 64
drivers/net/ethernet/intel/igb/igb_main.c:3092:53: warning: ‘%d’ directive output may be truncated writing between 1 and 5 bytes into a region of size between 1 and 13 [-Wformat-truncation=]
drivers/net/ethernet/intel/igb/igb_main.c:3092:34: note: directive argument in the range [0, 65535]
drivers/net/ethernet/intel/igb/igb_main.c:3092:34: note: directive argument in the range [0, 65535]
drivers/net/ethernet/intel/igb/igb_main.c:3090:25: note: ‘snprintf’ output between 23 and 43 bytes into a destination of size 32

Suggested-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://lore.kernel.org/r/20231017190411.2199743-2-jacob.e.keller@intel.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>