dma-buf: fix S_IRUGO to 0444, block comments, func declaration

These warnings/errors are reported by checkpatch.
Fix them with minor changes to make it clean.
No other functional changes.

WARNING: Block comments use * on subsequent lines
+       /* only support discovering the end of the buffer,
+          but also allow SEEK_SET to maintain the idiomatic

WARNING: Block comments use a trailing */ on a separate line
+          SEEK_END(0), SEEK_CUR(0) pattern */

WARNING: Block comments use a trailing */ on a separate line
+        * before passing the sgt back to the exporter. */

ERROR: "foo * bar" should be "foo *bar"
+static struct sg_table * __map_dma_buf(struct dma_buf_attachment *attach,

WARNING: Symbolic permissions 'S_IRUGO' are not preferred. Consider using octal permissions '0444'.
+       d = debugfs_create_file("bufinfo", S_IRUGO, dma_buf_debugfs_dir,

total: 1 errors, 4 warnings, 1746 lines checked

Signed-off-by: Pintu Kumar <quic_pintu@quicinc.com>
Acked-by: John Stultz <jstultz@google.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20241005180955.6523-1-quic_pintu@quicinc.com