arm64/sysreg: fix odd line spacing

arm64/sysreg: fix odd line spacing

Between the header and the definitions, there's no line gap, and in a
couple of places a double line gap for no semantic reason, which makes
the output look a little odd.

Fix this so blocks are consistently separated with a single line gap:

* Add a newline after the "Generated file" comment line, so this is
  clearly split from whatever the first definition in the file is.

* At the start of a SysregFields block there's no need for a newline as
  we haven't output any sysreg encoding details prior to this.

* At the end of a Sysreg block there's no need for a newline if we
  have no RES0 or RES1 fields, as there will be a line gap after the
  previous element (e.g. a Fields line).

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220513174118.266966-3-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>