libc/glibc: spelling fixes in the menuconfig help entries

nits:
- fix the spelling of changing.
- 'chose' is the correct past tense.

Signed-off-by: Michael Hope <michael.hope@linaro.org>

 # Compute s390-specific values

 CT_DoArchTupleValues() {

     # That's the only thing to override

     if [ "${CT_ARCH_64}" = "y" ]; then

         CT_TARGET_ARCH="s390x"

     fi

 }