Windows: Replace the sanitize_path() function with normalize_path()

Once upon a time the sanitize_path() function was needed to generate a
consistent path format in order to hash the resulting string for use as
session IDs. Since commit 71a779d078 ("Windows: Rework WinUSB
enumeration process to fix issues on Win8+"), this hashing method is no
longer used for session IDs, thus the sanitize_path() function was no
longer explicitly needed.

User lo1ol also reports in issue #633 that the function actually causes
issues with devices where there is a path component following the device
interface GUID. Rather than patching the function to fix this specific
behavior, just replace it with a simpler function that returns an
uppercased duplicate of the input string.

Closes #633, Closes #662

Signed-off-by: Chris Dickens <christopher.a.dickens@gmail.com>