fbdev: nvidiafb: add depends on HAS_IOPORT

The nvidiafb driver uses inb()/outb() without depending on HAS_IOPORT,
which leads to build errors since kernel v6.13-rc1:
commit 6f043e75 ("asm-generic/io.h: Remove I/O port accessors
for HAS_IOPORT=n")

Add the HAS_IOPORT dependency to prevent the build errors.

(Found in ARCH=um allmodconfig builds)

drivers/video/fbdev/nvidia/nv_accel.c: In function ‘NVDmaWait’:
include/asm-generic/io.h:596:15: error: call to ‘_outb’ declared with attribute error: outb() requires CONFIG_HAS_IOPORT
  596 | #define _outb _outb

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: stable@vger.kernel.org # v6.13+
Signed-off-by: Helge Deller <deller@gmx.de>