ARM: pxa: select both FB and FB_W100 for eseries

We get a link error trying to access the w100fb_gpio_read/write
functions from the platform when the driver is a loadable module
or not built-in, so the platform already uses 'select' to hard-enable
the driver.

However, that fails if the framebuffer subsystem is disabled
altogether.

I've considered various ways to fix this properly, but they
all seem like too much work or too risky, so this simply
adds another 'select' to force the subsystem on as well.

Fixes: 82427de2 ("ARM: pxa: PXA_ESERIES depends on FB_W100.")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>