[ARM] 4410/1: Remove extern declarations in coyote/ixdpg425-pci.c

This patch removes apparently unnecessary extern declarations in
coyote-pci.c and ixdpg425-pci.c within arch/arm/mach-ixp4xx and
has been compile-tested without producing warnings or errors.

Kernel coding style forbids the use of extern declarations within .c
files.

Signed-off-by: Michael-Luke Jones <mlj28@cam.ac.uk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>