video: driver: amend priorities to allow more sessions

1. adjust client set non-realtime priroty with NRT_PRIORITY_OFFSET (2)
2. if total mbps is more than max_mbps
    a. allow encode session by reducing decoder sessions priority by 1
    b. allow decode session by moving it to non-realtime session
        in order to not disturb the ongoing sessions

Change-Id: I96fd2ac75c123d681982fb9a2c06ac51d15bd59a
Signed-off-by: Deepa Guthyappa Madivalara <quic_dmadival@quicinc.com>

driver/vidc/inc/msm_vidc_internal.h

@@ -31,6 +31,8 @@
 #define DEFAULT_WIDTH     320
 #define DEFAULT_FPS       30
 #define MAXIMUM_VP9_FPS   60
+#define NRT_PRIORITY_OFFSET        2
+#define RT_DEC_DOWN_PRORITY_OFFSET 1
 #define MAX_SUPPORTED_INSTANCES  16
 #define DEFAULT_BSE_VPP_DELAY    2
 #define MAX_CAP_PARENTS          20