s390: cio: fix cio_irb declaration

clang points out that the declaration of cio_irb does not match the
definition exactly, it is missing the alignment attribute:

../drivers/s390/cio/cio.c:50:1: warning: section does not match previous declaration [-Wsection]
DEFINE_PER_CPU_ALIGNED(struct irb, cio_irb);
^
../include/linux/percpu-defs.h:150:2: note: expanded from macro 'DEFINE_PER_CPU_ALIGNED'
        DEFINE_PER_CPU_SECTION(type, name, PER_CPU_ALIGNED_SECTION)     \
        ^
../include/linux/percpu-defs.h:93:9: note: expanded from macro 'DEFINE_PER_CPU_SECTION'
        extern __PCPU_ATTRS(sec) __typeof__(type) name;                 \
               ^
../include/linux/percpu-defs.h:49:26: note: expanded from macro '__PCPU_ATTRS'
        __percpu __attribute__((section(PER_CPU_BASE_SECTION sec)))     \
                                ^
../drivers/s390/cio/cio.h:118:1: note: previous attribute is here
DECLARE_PER_CPU(struct irb, cio_irb);
^
../include/linux/percpu-defs.h:111:2: note: expanded from macro 'DECLARE_PER_CPU'
        DECLARE_PER_CPU_SECTION(type, name, "")
        ^
../include/linux/percpu-defs.h:87:9: note: expanded from macro 'DECLARE_PER_CPU_SECTION'
        extern __PCPU_ATTRS(sec) __typeof__(type) name
               ^
../include/linux/percpu-defs.h:49:26: note: expanded from macro '__PCPU_ATTRS'
        __percpu __attribute__((section(PER_CPU_BASE_SECTION sec)))     \
                                ^
Use DECLARE_PER_CPU_ALIGNED() here, to make the two match.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>