MFC fbd(4) and vt_fb disentanglement:

r268472 (ray):

Should check fb_read method presence instead of double check for fb_write.

r269620 (nwhitehorn):

Retire various intertwined bits of fbd(4) and vt_fb, in particular the
pixel modification indirection. No actual drivers use it and those
that might (e.g. creatorfb) use custom implementations of
vd_bitbltchr().

Relnotes: No
Sponsored by: The FreeBSD Foundation

MFC r268771, r268796 by nwhitehorn:

r268771:
Allow console drivers active from early boot to be used with
xf86-video-scfb, rather than only drivers attached later on. This
involves a small amount of code duplication with dev/fb/fbd.c, which
will fixed later on.

Also improve performance of vt_blank() by making it not read from the
framebuffer unnecessarily.

r268796:
Fix embarassing typos I made.

Sponsored by: The FreeBSD Foundation

MFC 259016,259019,259049,259071,259102,259110,259129,259130,259178,259179,
259203,259221,259261,259532,259615,259650,259651,259667,259680,259727,
259761,259772,259776,259777,259830,259882,259915,260160,260449,260450,
260688,260888,260953,261269,261547,261551,261552,261553,261585:
Merge the vt(4) driver (newcons) to stable/10.

Approved by: ray

MFC fbd(4) and vt_fb disentanglement:

r268472 (ray):

Should check fb_read method presence instead of double check for fb_write.

r269620 (nwhitehorn):

Retire various intertwined bits of fbd(4) and vt_fb, in particular the
pixel modification indirection. No actual drivers use it and those
that might (e.g. creatorfb) use custom implementations of
vd_bitbltchr().

Relnotes: No
Sponsored by: The FreeBSD Foundation

MFC r268771, r268796 by nwhitehorn:

r268771:
Allow console drivers active from early boot to be used with
xf86-video-scfb, rather than only drivers attached later on. This
involves a small amount of code duplication with dev/fb/fbd.c, which
will fixed later on.

Also improve performance of vt_blank() by making it not read from the
framebuffer unnecessarily.

r268796:
Fix embarassing typos I made.

Sponsored by: The FreeBSD Foundation

MFC 259016,259019,259049,259071,259102,259110,259129,259130,259178,259179,
259203,259221,259261,259532,259615,259650,259651,259667,259680,259727,
259761,259772,259776,259777,259830,259882,259915,260160,260449,260450,
260688,260888,260953,261269,261547,261551,261552,261553,261585:
Merge the vt(4) driver (newcons) to stable/10.

Approved by: ray