Bluetooth: hci_intel: Fix multiple issues reported by checkpatch.pl

This fixes the following CHECKs, WARNINGs, and ERRORs reported in
hci_intel.c

Reported by checkpatch.pl:
-----------
hci_intel.c
-----------
WARNING: Prefer using '"%s...", __func__' to using 'intel_setup', this
        function's name, in a string
+       bt_dev_dbg(hdev, "start intel_setup");

ERROR: code indent should use tabs where possible
+        /* Check for supported iBT hardware variants of this firmware$

ERROR: code indent should use tabs where possible
+         * loading method.$

ERROR: code indent should use tabs where possible
+         *$

ERROR: code indent should use tabs where possible
+         * This check has been put in place to ensure correct forward$

ERROR: code indent should use tabs where possible
+         * compatibility options when newer hardware variants come along.$

ERROR: code indent should use tabs where possible
+         */$

CHECK: No space is necessary after a cast
+       duration = (unsigned long long) ktime_to_ns(delta) >> 10;

CHECK: No space is necessary after a cast
+       duration = (unsigned long long) ktime_to_ns(delta) >> 10;

WARNING: Missing a blank line after declarations
+               int err = PTR_ERR(intel->rx_skb);
+               bt_dev_err(hu->hdev, "Frame reassembly failed (%d)", err);

Signed-off-by: Uri Arev <me@wantyapps.xyz>
Suggested-by: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>