i40e: Fix off by one in i40e_dbg_command_write
i40e: Fix off by one in i40e_dbg_command_write

We assume that the resulting buffer is zero terminated when we then
re-use it. The sscanf is limited to 512 bytes but needs to be 511
to allow for a terminator.

One of a set of problems noted by Jackie Chang

Signed-off-by: Alan Cox <91e38e63b890fbb214c8914809fde03c73e7f24d@linux.intel.com>
Acked-by: Shannon Nelson <5d931f7cba4ffa13f18563a31991f031b90116ee@intel.com>
Tested-by: Kavindya Deegala <0716ac131ef4b886955b7082f827ccaacb3c2837@intel.com>
Signed-off-by: Jeff Kirsher <87e35f5be20bb3e67f4ba6b86f5f6be3085b1b3a@intel.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs