net/freerdp: Update to 2.6.0

Update to 2.6.0 and remove patch for old versions of libusb. All
supported versions of the FreeBSD have newer version of the libusb and
patch is obsoleted.

Changelog (https://github.com/FreeRDP/FreeRDP/releases/tag/2.6.0):

• Noteworthy changes:
  • Backported android FFMPEG build scripts
  • Updated android build dependencies
• Fixed issues:
  • Backported #7303: Fix PDU length for RDPINPUT_PROTOCOL_V300
  • Backported #7658: Sanitize optional physical monitor size values
  • Backported #7426: Wayland memory corruption
  • Backported #7293: Remove unused codec x264
  • Backported #7541: Allow resolutions larger 2048x2048
  • Backported #7574: FFMPEG 5.0 support
  • Backported #7578: FFMPEG 5.0 support
  • Backported #7580: Fixed device hotplugging
  • Backported #7583: GetUserNameExA: Prefer getpwuid_r over getlogin_r over getlogin
  • Backported #7585: Android Mediacodec support

PR: 262163