hcidump: Fix HCI LE advertising report dump

hcidump: Fix HCI LE advertising report dump

LE advertising report event has only one data block for each report.
Thus, we can't reuse ext_inquiry_response_dump(), which loops over
successive data blocks until reaches a zero-length one.

This commit introduces ext_inquiry_data_dump(), which dumps a frame
containing data formatted according to [Vol 3] Part C, Section 8. This
function is reused by ext_inquiry_response_dump().

Also adds RSSI parsing to each advertising report.