drivers: thermal: Use FCAP scm call instead of DMAX in LMH DCVSh

LMH-DCVSh driver right now achieves the software mitigation by using
the domain max scm call. But this could have some delays in clearing
the mitigation.

To avoid the delay, use the frequency cap scm call to place the
mitigation.

Change-Id: I00f1b2534505e02c8e66f6ce8088c37bfbb98198
Signed-off-by: Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org>