ARM: pxa: cm-x2xx: avoid duplicate macro warnings

In an old commit, we worked around the duplicate definition of
GPIO24_SSP1_SFRM in cm-x2xx.c, which includes files for both
pxa25x and pxa27x. Apparently the problem has come back and we
now have four additional duplicate symbols that cause warnings:

In file included from /git/arm-soc/arch/arm/mach-pxa/pxa27x.h:7:0,
                 from /git/arm-soc/arch/arm/mach-pxa/cm-x2xx.c:27:
/git/arm-soc/arch/arm/mach-pxa/mfp-pxa27x.h:21:0: warning: "GPIO86_GPIO" redefined
 #define GPIO86_GPIO  MFP_CFG_IN(GPIO86, AF0)

This uses the same hack as before and undefines all symbols that
are defined more than once. Fortunately, cm-x2xx does not need
any of these.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>