defconfig: arm64: msm-perf: enable FB_MSM_MDSS_XLOG_DEBUG

Enable FB_MSM_MDSS_XLOG_DEBUG for enabled XLOG debugging in
MDSS driver. These XLOG enablement provide additional information
when there is a critical error in display driver during stability
tests.

Change-Id: Ic49b4cc42a5dc14d065791b5653638c3a9ab0bc2
Signed-off-by: Jeevan Shriram <jshriram@codeaurora.org>