arm64: Fix silcon-errata.rst formatting

Remove the errant blank lines to make the desired empty row separators
around the Fujitsu and ASR entries in the main table, rather than them
being their own separate tables which then look odd in the HTML view.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/b6637654eda761e224f828a44a7bbc1eadf2ef88.1705511145.git.robin.murphy@arm.com


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