gpio: dwapb: remove dependencies

The Synopsys DesignWare DWAPB GPIO block is popular to
synthesize amongst many architectures: X86, ARM, ARC.
The driver was restricted to only these archs due to
using [read|write]l_relaxed() accessors that were not
universally available in the past,
but as of commit 9439eb3a
"asm-generic: io: implement relaxed accessor macros as
conditional wrappers" these accessors are available on all
archs so this should not be a problem any more. Enable the
driver for all archs.

Cc: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>