qcacmn: Add cache invalidation for MIPS platforms

Add cache invalidation support for for MIPS platforms. The API
on mips platform takes start and size as input. Obtain size by
subtracting end and start.

Change-Id: Iaf2920b8fed2b2a2870682c6bf75c905cb8ca836

qdf/linux/src/i_qdf_nbuf_w.h

@@ -147,6 +147,13 @@ __qdf_nbuf_dma_inv_range(const void *buf_start, const void *buf_end)
 {
 	dmac_inv_range(buf_start, buf_end);
 }
+#elif defined(__LINUX_MIPS32_ARCH__) || defined(__LINUX_MIPS64_ARCH__)
+static inline void
+__qdf_nbuf_dma_inv_range(const void *buf_start, const void *buf_end)
+{
+	dma_cache_inv((unsigned long)buf_start,
+		      (unsigned long)(buf_end - buf_start));
+}
 #else
 static inline void
 __qdf_nbuf_dma_inv_range(const void *buf_start, const void *buf_end)