powerpc/pci: Always print PHB and PE numbers as hexadecimal

PHB, PE (and by association MVE) numbers are printed as a mix of decimal
and hexadecimal throughout the kernel.  This can be misleading, so make
them all hexadecimal.

Standardising on hex instead of dec because:

 - PHB numbers are presented in hex in sysfs/debugfs (and lspci, etc)
 - PE numbers are presented as hex in sysfs and parsed in hex in debugfs

The only place I think this could cause confusing are the messages during
boot, i.e.

	pci 000a:01     : [PE# 000] Secondary bus 1 associated with PE#0

which can be a quick way to check PE numbers.  pe_level_printk() will
only print two characters instead of three, so the above would be

	pci 000a:01     : [PE# 00] Secondary bus 1 associated with PE#0

which gives a hint it's in hex.

Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>