arm/imx: remove mx27_setup_weimcs() from mx27.h

The helper function mx27_setup_weimcs() references IOMEM() and
IMX_IO_P2V() but without required header mach/hardware.h included
in mx27.h.  This will break the build of those mx27 file with no
direct inclusion of mach/hardware.h, or when indirect inclusion to
mach/hardware.h breaks.

For example, when the inclusion of mach/hardware.h gets removed from
mach/gpio.h, we will see the following compile error.

  CC      arch/arm/mach-imx/pm-imx27.o
In file included from arch/arm/mach-imx/pm-imx27.c:14:0:
arch/arm/plat-mxc/include/mach/mx27.h: In function ‘mx27_setup_weimcs’:
arch/arm/plat-mxc/include/mach/mx27.h:138:2: error: implicit declaration of function ‘IOMEM’
arch/arm/plat-mxc/include/mach/mx27.h:138:2: error: implicit declaration of function ‘IMX_IO_P2V’

This patch removes mx27_setup_weimcs() from mx27.h and makes it local
to mach-pcm038.c, which is the only user for this helper.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>