e1000e: cleanup magic number

Signed-off-by: NBruce Allan <bruce.w.allan@intel.com>
Tested-by: NAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/e1000e/nvm.c

@@ -464,8 +464,8 @@ s32 e1000_read_pba_string_generic(struct e1000_hw *hw, u8 *pba_num,
 	if (nvm_data != NVM_PBA_PTR_GUARD) {
 		e_dbg("NVM PBA number is not stored as string\n");
 
-		/* we will need 11 characters to store the PBA */
-		if (pba_num_size < 11) {
+		/* make sure callers buffer is big enough to store the PBA */
+		if (pba_num_size < E1000_PBANUM_LENGTH) {
 			e_dbg("PBA string buffer too small\n");
 			return E1000_ERR_NO_SPACE;
 		}