arm64: Kconfig: select ALPINE_MSI only if PCI is selected

Even when PCI is disabled, ARCH_ALPINE selects ALPINE_MSI triggerring
the following config warning:

warning: (ARCH_ALPINE) selects ALPINE_MSI which has unmet direct
		dependencies (PCI)

This patch makes selection of ALPINE_MSI conditional on PCI.

Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>