Fix invalid bit-field

[dg0yt]

Fixes gcc compiler error when using msh3:

In file included from /vcpkg/scripts/test_ports/vcpkg-ci-msh3/project/main.c:1:
/vcpkg/installed/x64-linux/include/msh3.h:377:18: error: width of ‘RESERVED’ exceeds its type
  377 |             bool RESERVED                 : 5;
      |                  ^~~~~~~~
/vcpkg/installed/x64-linux/include/msh3.h:490:18: error: width of ‘RESERVED’ exceeds its type
  490 |             bool RESERVED            : 7;
      |                  ^~~~~~~~

According to https://en.cppreference.com/w/c/language/bit_field, the width is "an integer constant expression with a value greater or equal to zero and less or equal the number of bits in the underlying type. So for a one-bit bool type, width cannot exceed 1.

Noticed in the vcpkg test port for msh3.