Fixed "config.pl get" for options with no value
Fixed "config.pl get" for options with no value

Between 2.5.0 and 2.6.0, "scripts/config.pl get MBEDTLS_XXX" was fixed
for config.h lines with a comment at the end, but that broke the case
of macros with an empty expansion. Support all cases.

ARMmbed/mbedtls,NXPmicro/mbedtls,ARMmbed/mbedtls,NXPmicro/mbedtls,ARMmbed/mbedtls,Mbed-TLS/mbedtls,ARMmbed/mbedtls,Mbed-TLS/mbedtls,NXPmicro/mbedtls,Mbed-TLS/mbedtls,Mbed-TLS/mbedtls,NXPmicro/mbedtls