v3dv: refactor meta copy/clear code

v3dv: refactor meta copy/clear code

This change does the following:

- Moves image clearing code from v3dv_meta_copy.c to v3dv_meta_clear.c
  where it belongs.
- Renames v3dv_meta_copy.h to v3dv_meta_common.h since now it is required
  by the copy and clear code.
- Renames 'struct framebuffer_data' type.
- Merges v3dvx_meta_clear.c and v3dvx_meta_copy.c into v3dvx_meta_common.c.
- Prefixes all "public" meta functions with the 'meta' prefix.

Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11902>