vbo: Return INVALID_OPERATION during draw with a mapped buffer

vbo: Return INVALID_OPERATION during draw with a mapped buffer

Fixes the OpenGLES 3.1 CTS:
 * ESEXT-CTS.draw_elements_base_vertex_tests.invalid_mapped_bos

Because this is triggering the error message after the normal API
validation phase, we don't have the API function name available, and
therefore we generate an error message without the draw call name:

Mesa: User error: GL_INVALID_OPERATION in draw call (vertex buffers are mapped)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=95142
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>