ec/asm/ecp_nistz256-x86_64.pl: fix inconsistency in path handling.

# VIA Nano	+37-130%

#

# Ranges denote minimum and maximum improvement coefficients depending

# on benchmark.

# on benchmark. Lower coefficients are for ECDSA sign, relatively

# fastest server-side operation.

$flavour = shift;

$output  = shift;

# Convert ecp_nistz256_table.c to layout expected by ecp_nistz_gather_w7

#

open TABLE,"<ecp_nistz256_table.c"		or 

open TABLE,"<${dir}/../ecp_nistz256_table.c"	or 

open TABLE,"<${dir}../ecp_nistz256_table.c"	or 

die "failed to open ecp_nistz256_table.c:",$!;

use integer;