kconfig: make use of menu_get_ext_help in menuconfig
kconfig: make use of menu_get_ext_help in menuconfig

The removed functions are moved into menu.c for sharing with
gconfig & xconfig & config.

Signed-off-by: Cheng Renquan <9005d0112f8b7a9031d4722bf4b49b99662ccb21@gmail.com>
Cc: Roman Zippel <f9f6ad990b4a8c1974dc6544787c1cc3570b6f00@linux-m68k.org>
Signed-off-by: Sam Ravnborg <f16bed56189e249fe4ca8ed10a1ecae60e8ceac0@ravnborg.org>

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