[ARM] Support correctly spelled ARMv6KZ architecture names

[ARM] Support correctly spelled ARMv6KZ architecture names

2015-07-20  Matthew Wahab  <matthew.wahab@arm.com>

gas/
    * NEWS: Mention corrected spelling of armv6kz.
    * config/tc-arm.c (arm_cpus): Replace ARM_ARCH_V6ZK with
    ARM_ARCH_V6KZ.
    (arm_archs): Likewise. Also add "armv6kz" and "armv6kzt2".
    * doc/c-arm.texi: Replace "armv6zk" with "armv6kz".

gas/testsuite

    * gas/arm/attr-march-armv6kz.d: New.
    * gas/arm/attr-march-armv6kzt2.d: New.

include/opcode

    * arm.h (ARM_AEXT_V6ZK): Rename to ARM_AEXT_V6KZ.
    (ARM_AEXT_V6ZKT2): Rename to ARM_AEXT_V6KZT2.
    (ARM_ARCH_V6ZK): Rename to ARM_ARCH_V6KZ.
    (ARM_ARCH_V6ZKT2): Rename to ARM_ARCH_V6KZT2.