doc: Update mentions of README.fdt-control

Update documents 'README.fdt-control' reference to replacement 'control.rst':
  doc/arch/nios2.rst
  dts/Makefile

Also convert some adjacent pathname mentions to rST links where applicable

Fixes: 3e9fddfc4f "doc: Move devicetree control doc to rST"
Signed-off-by: E Shattow <e@freeshell.de>

doc/develop/devicetree/control.rst

@@ -282,7 +282,7 @@ U-Boot can be divided into three phases: TPL, SPL and U-Boot proper.
 
 The full devicetree is available to U-Boot proper, but normally only a subset
 (or none at all) is available to TPL and SPL. See 'Pre-Relocation Support' and
-'SPL Support' in doc/driver-model/design.rst for more details.
+'SPL Support' in :doc:`/develop/driver-model/design` for more details.
 
 
 Using several DTBs in the SPL (SPL_MULTI_DTB_FIT Kconfig option)

doc/develop/driver-model/ethernet.rst

@@ -8,7 +8,7 @@ own ethernet device driver.  Here we will describe a new pseudo 'APE' driver.
 
 Most existing drivers do already - and new network driver MUST - use the
 U-Boot core driver model. Generic information about this can be found in
-doc/driver-model/design.rst, this document will thus focus on the network
+:doc:`/develop/driver-model/design`, this document will thus focus on the network
 specific code parts.
 Some drivers are still using the old Ethernet interface, differences between
 the two and hints about porting will be handled at the end.

doc/develop/spl.rst

@@ -145,7 +145,7 @@ fdtgrep is also used to remove:
   'bootph-verify' (VPL))
 
 All the nodes remaining in the SPL devicetree are bound
-(see doc/driver-model/design.rst).
+(see :doc:`/develop/driver-model/design`).
 
 NOTE: U-Boot migrated to a new schema for the u-boot,dm-* tags in 2023. Please
 update to use the new bootph-* tags as described in the