MAINTAINERS: rectify entry for INTEL KEEM BAY OCS ECC CRYPTO DRIVER

Commit c9f608c3 ("crypto: keembay-ocs-ecc - Add Keem Bay OCS ECC
Driver") only adds drivers/crypto/keembay/keembay-ocs-ecc.c, but adds a
file entry drivers/crypto/keembay/ocs-ecc-curve-defs.h in MAINTAINERS.

Hence, ./scripts/get_maintainer.pl --self-test=patterns warns:

  warning: no file matches  F:  drivers/crypto/keembay/ocs-ecc-curve-defs.h

Assuming that this header is obsolete and will not be included in the
repository, remove the unneeded file entry from MAINTAINERS.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Daniele Alessandrelli <daniele.alessandrelli@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>