prima: Purge oldest scan entry if max BSS limit reached

In the driver, while processing the scan results, if the max
BSS limit is reached, all the newest scan results are dropped
and stale scan results are updated to upper layers.

To address this, remove the oldest scan entry if the max
BSS limit is reached.

Change-Id: Ib85a8a3b66fbf903311002887a3c5c3d10bfbccf
CRs-Fixed: 991417
diff --git a/CORE/SME/src/csr/csrInsideApi.h b/CORE/SME/src/csr/csrInsideApi.h
index c343262..f05fcd4 100644
--- a/CORE/SME/src/csr/csrInsideApi.h
+++ b/CORE/SME/src/csr/csrInsideApi.h
@@ -68,7 +68,7 @@
 
 #define CSR_MAX_2_4_GHZ_SUPPORTED_CHANNELS 14
 
-#define CSR_MAX_BSS_SUPPORT            250
+#define CSR_MAX_BSS_SUPPORT            512
 #define SYSTEM_TIME_MSEC_TO_USEC      1000
 
 //This number minus 1 means the number of times a channel is scanned before a BSS is remvoed from