misc: fix the uninitialization error

misc: fix the uninitialization error

Type: fix

| src/vppinfra/vector/toeplitz.c:69:9: error: ‘kv’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
| src/vppinfra/memcpy_x86_64.h:45:17: error: ‘*((void *)&key+16)’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
|    *(u8x16u *) d = *(u8x16u *) s;
|    ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~
| src/vnet/gre/interface.c:356:20: note: ‘*((void *)&key+16)’ was declared here

Signed-off-by: Mohsin Kazmi <sykazmi@cisco.com>
Change-Id: I71614da2821ebda5200a0cb9437a7aad0c42fbb2