ARM: pxa: remove eseries.h

Commit e478fe4c ("[ARM] pxa: merge all
eseries board code into eseries.c") removed all six files that included
eseries.h. Everything that this header provides is now either local to
eseries.c or entirely unused. It was apparently just an oversight to
keep this header. This header can safely be removed.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Tested-by: Eric Miao <eric.y.miao@gmail.com>
Signed-off-by: Haojian Zhuang <haojian.zhuang@gmail.com>