uboot-imx

pci.h: allow inclusion in assembly source

This patch simply #ifdef's out the C-specific parts of pci.h when it is
included by an assembly file. This will allow the macros it contains to
be used from assembly source as will be done in a followup commit adding
support for more modern MIPS Malta boards.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>