microblaze: Remove noMMU code

This configuration is obsolete and likely none is really using it. That's
why remove it to simplify code.

Note about CONFIG_MMU in hw_exception_handler.S is left intentionally
for better comment understanding.

Cc: Mike Rapoport <rppt@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/43486cab370e0c0a79860120b71e0caac75a7e44.1606397528.git.michal.simek@xilinx.com
diff --git a/arch/microblaze/Makefile b/arch/microblaze/Makefile
index 7b340a3..bb98089 100644
--- a/arch/microblaze/Makefile
+++ b/arch/microblaze/Makefile
@@ -1,11 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 KBUILD_DEFCONFIG := mmu_defconfig
 
-ifeq ($(CONFIG_MMU),y)
 UTS_SYSNAME = -DUTS_SYSNAME=\"Linux\"
-else
-UTS_SYSNAME = -DUTS_SYSNAME=\"uClinux\"
-endif
 
 # What CPU vesion are we building for, and crack it open
 # as major.minor.rev
@@ -67,12 +63,7 @@
 
 core-y	+= $(boot)/dts/
 
-# defines filename extension depending memory management type
-ifeq ($(CONFIG_MMU),)
-MMU := -nommu
-endif
-
-export MMU DTB
+export DTB
 
 all: linux.bin