pvr2fb: Fix oops when pseudo_palette is written

Reported by: Adrian McMenamin <adrianmcmenamin@gmail.com>

This driver will oops when the pseudo_palette[] is written as u32 but not when
written as u16.  When written as u32, it corrupts the adjacent 'mmio_base'
field of struct pvr2fb_par.  Fix by using framebuffer_alloc()/release() to
allocate struct fb_info and struct pvr2fb_par, and create the pseudo_palette[]
as part of struct pvr2fb_par.

Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>