kbuild: remove kconfig binaries during make mrproper
kbuild: remove kconfig binaries during make mrproper

Nigel Cunningham <cfea2496442c091fddd1ba215d62a69ec34e94d0@nigel.suspend2.net> noticed
that 'make mrproper' did not remove mconf.
Fixed so we now remove all relevant binaries.

Signed-off-by: Sam Ravnborg <f16bed56189e249fe4ca8ed10a1ecae60e8ceac0@ravnborg.org>
Cc:  Nigel Cunningham <cfea2496442c091fddd1ba215d62a69ec34e94d0@nigel.suspend2.net>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs