The existing htcherald_defconfig did not include mux support, which
prevented USB and other functionality from working out of the box.
This change updates the defconfig to add it in.  It also aligns the
defconfig to the -rc8 kernel config.
Signed-off-by: Cory Maccarrone <darkstar6262@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>