Documentation/arm64: fix RST layout of memory.rst

Stephen reports that commit f4693c27 ("arm64: mm: extend linear region
for 52-bit VA configurations") triggers the following warnings when building
the htmldocs make target of today's linux-next:

  Documentation/arm64/memory.rst:35: WARNING: Literal block ends without a blank line; unexpected unindent.
  Documentation/arm64/memory.rst:53: WARNING: Literal block ends without a blank line; unexpected unindent.

Let's tweak the memory layout table to work around this.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Fixes: f4693c27 ("arm64: mm: extend linear region for 52-bit VA configurations")
Link: https://lore.kernel.org/r/20201110130851.15751-1-ardb@kernel.orgSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>

Documentation/arm64/memory.rst

@@ -32,7 +32,7 @@ AArch64 Linux memory layout with 4KB pages + 4 levels (48-bit)::
   -----------------------------------------------------------------------
   0000000000000000	0000ffffffffffff	 256TB		user
   ffff000000000000	ffff7fffffffffff	 128TB		kernel logical memory map
-[ ffff600000000000	ffff7fffffffffff ]	  32TB		[ kasan shadow region ]
+ [ffff600000000000	ffff7fffffffffff]	  32TB		[kasan shadow region]
   ffff800000000000	ffff800007ffffff	 128MB		bpf jit region
   ffff800008000000	ffff80000fffffff	 128MB		modules
   ffff800010000000	fffffbffefffffff	 124TB		vmalloc
@@ -50,7 +50,7 @@ AArch64 Linux memory layout with 64KB pages + 3 levels (52-bit with HW support):
   -----------------------------------------------------------------------
   0000000000000000	000fffffffffffff	   4PB		user
   fff0000000000000	ffff7fffffffffff	  ~4PB		kernel logical memory map
-[ fffd800000000000	ffff7fffffffffff ]	 512TB		[ kasan shadow region ]
+ [fffd800000000000	ffff7fffffffffff]	 512TB		[kasan shadow region]
   ffff800000000000	ffff800007ffffff	 128MB		bpf jit region
   ffff800008000000	ffff80000fffffff	 128MB		modules
   ffff800010000000	fffffbffefffffff	 124TB		vmalloc