update_headers.sh: Remove arm architecture

KVM host support for the arm architecture was removed in commit
541ad0150ca4 ("arm: Remove 32bit KVM host support"). When trying to sync
KVM headers we get this error message:

$ util/update_headers.sh /path/to/linux
cp: cannot stat '/path/to/linux/arch/arm/include/uapi/asm/kvm.h': No such file or directory

Do not attempting to copy KVM headers for that architecture.

Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Link: https://lore.kernel.org/r/20200810153828.216821-1-alexandru.elisei@arm.com


Signed-off-by: Will Deacon <will@kernel.org>