defconfig: msm8974: Disable MSMSAMARIUM support

Do not compile support for the MSMSAMARIUM target for
kernels built using the msm8974_defconfig.

Change-Id: I8021330fea97b19ade16d5fad77d5e6fc0e4ed06
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>