cmake: Fix typo of waffle_build_htmldocs
cmake: Fix typo of waffle_build_htmldocs

In Options.cmake, s/waffle_build_htmldoc/waffle_build_htmldocs/

Signed-off-by: Chad Versace <a557f7f75bf28dc19ac99107f5cc7cd6b3fbdb1a@linux.intel.com>

evelikov/waffle,fjhenigman/waffle,dcbaker/waffle,waffle-gl/waffle,yinquan529/waffle-gl-waffle,dcbaker/waffle,maurossi/waffle,janesma/waffle,janesma/waffle,janesma/waffle,evelikov/waffle,yinquan529/waffle-gl-waffle,fjhenigman/waffle,maurossi/waffle,chadversary/waffle,yinquan529/waffle-gl-waffle,waffle-gl/waffle,evelikov/waffle,waffle-gl/waffle,chadversary/waffle,waffle-gl/waffle,chadversary/waffle,fjhenigman/waffle,maurossi/waffle,dcbaker/waffle