parisc: drop include of asm/pdc.h from asm/hardware.h

It seems none of the symbols defined by pdc.h is needed, but it introduces an
include loop causing compile errors:

In file included from arch/parisc/include/asm/spinlock.h:4:0,
                 from arch/parisc/include/asm/atomic.h:20,
                 from include/linux/atomic.h:4,
                 from arch/parisc/include/asm/bitops.h:56,
                 from include/linux/bitops.h:35,
                 from include/asm-generic/getorder.h:7,
                 from arch/parisc/include/asm/page.h:162,
                 from arch/parisc/include/asm/pdc.h:346,
                 from arch/parisc/include/asm/hardware.h:5,
                 from arch/parisc/kernel/hardware.c:30:
arch/parisc/include/asm/processor.h:74:16: error: field ‘cpu_type’ has incomplete type
arch/parisc/include/asm/processor.h:77:20: error: field ‘model’ has incomplete type
arch/parisc/include/asm/processor.h: In function ‘parisc_requires_coherency’:
arch/parisc/include/asm/processor.h:349:36: error: ‘mako’ undeclared (first use in this function)
arch/parisc/include/asm/processor.h:349:36: note: each undeclared identifier is reported only once for each function it appears in
arch/parisc/include/asm/processor.h:350:30: error: ‘mako2’ undeclared (first use in this function)

Signed-off-by: Rolf Eike Beer <eike-kernel@sf-tec.de>
Acked-by: Grant Grundler <grantgrundler@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>