Revert zvc_check_encdec() and use variables

Author: nadime15

model/riscv_types_zvk.sail

@@ -6,4 +6,4 @@
 /*  SPDX-License-Identifier: BSD-2-Clause                                                */
 /*=======================================================================================*/
 
-function zvk_check_encdec(EGW: {128, 256}, EGS: {4, 8}) -> bool = (unsigned(vl) % EGS == 0) & (unsigned(vstart) % EGS == 0) & (2 ^ get_lmul_pow() * VLEN) >= EGW
+function zvk_check_encdec(EGW: int, EGS: int) -> bool = (unsigned(vl) % EGS == 0) & (unsigned(vstart) % EGS == 0) & (2 ^ get_lmul_pow() * VLEN) >= EGW