GDB: Guile: Remove procedures ineffectual since Guile 2.2

The manual mentions since GDB 10 that the functions for getting and setting
the size of memory port buffers are deprecated, and don't work when using
Guile 2.2 or later.  Since now GDB only supports Guile 2.2 and newer,
perform the promised removal.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-By: Tom Tromey <tom@tromey.com>
4 files changed