KVM: arm64: Increase number of user memslots to 512

Having only 32 memslots is a real constraint for the maximum
number of PCI devices that can be assigned to a single guest.
Assuming each PCI device/virtual function having two memory BAR
regions, we could assign only 15 devices/virtual functions to a
guest.

Hence increase KVM_USER_MEM_SLOTS to 512 as done in other archs like
powerpc.
Reviewed-by: NChristoffer Dall <cdall@linaro.org>
Signed-off-by: NLinu Cherian <linu.cherian@cavium.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

arch/arm64/include/asm/kvm_host.h

@@ -30,7 +30,7 @@
 
 #define __KVM_HAVE_ARCH_INTC_INITIALIZED
 
-#define KVM_USER_MEM_SLOTS 32
+#define KVM_USER_MEM_SLOTS 512
 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1
 #define KVM_HALT_POLL_NS_DEFAULT 500000