msm: mdss: disable fetch for all previous stages with is_fg
msm: mdss: disable fetch for all previous stages with is_fg

The is_fg flag is used to disable fetch for all previous mixer stages,
currently this only to disable fetch for base layer. Modify mixer setup
logic to disable fetch for all previous mixer stages.

CRs-Fixed: 413254
Change-Id: Ic0f101fe88a3c64db11cf43484f64f0f5e32d0d0
Signed-off-by: Adrian Salido-Moreno <f4561ccbe90a02dadc9d168b29bfea0c1b57222c@codeaurora.org>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas