[PowerPC] Remove obsolete MK_LOADER_FORCE_LE

In D12421, the ability to compile stand/ in little-endian was added, with the
intention to extend loader.kboot to run in Petitboot.

However, no further work was done, as the kernel then gained self-execution
capabilities as Petitboot was taught to load FreeBSD kernels directly.

The FreeBSD installer on powerpc64 (on POWER8 and POWER9) uses
/boot/etc/kboot.conf instead of loader.

As this option does nothing but cause stand/ to be miscompiled and actively
causes confusion, remove it.

(I have a functioning petitboot loader in my local tree, however, it turned
out to be quite inconvient to use due to the current petitboot plugin design
so I put it on hold.)

Reviewed by:	emaste, imp, jhibbits
Sponsored by:	Tag1 Consulting, Inc.
Differential Revision:	https://reviews.freebsd.org/D26430

share/man/man5/src.conf.5

@@ -1,6 +1,6 @@
 .\" DO NOT EDIT-- this file is @generated by tools/build/options/makeman.
 .\" $FreeBSD$
-.Dd September 11, 2020
+.Dd September 14, 2020
 .Dt SRC.CONF 5
 .Os
 .Sh NAME
@@ -983,9 +983,6 @@ with support for verification based on certificates obtained from UEFI.
 .It Va WITH_LOADER_FIREWIRE
 Enable firewire support in /boot/loader on x86. This option is a nop
 on all other platforms.
-.It Va WITH_LOADER_FORCE_LE
-Set to force the powerpc boot loader to launch the kernel in little
-endian mode.
 .It Va WITHOUT_LOADER_GELI
 Disable inclusion of GELI crypto support in the boot chain binaries.
 .Pp

share/mk/src.opts.mk

@@ -211,7 +211,6 @@ __DEFAULT_NO_OPTIONS = \
     HESIOD \
     LIBSOFT \
     LOADER_FIREWIRE \
-    LOADER_FORCE_LE \
     LOADER_VERBOSE \
     LOADER_VERIEXEC_PASS_MANIFEST \
     MALLOC_PRODUCTION \

stand/defs.mk

@@ -175,12 +175,6 @@ DD=dd ${DD_NOSTATUS}
 CFLAGS+=	-G0 -fno-pic -mno-abicalls
 .endif
 
-.if ${MK_LOADER_FORCE_LE} != "no"
-.if ${MACHINE_ARCH} == "powerpc64"
-CFLAGS+=	-mlittle-endian
-.endif
-.endif
-
 #
 # Have a sensible default
 #

tools/build/options/WITH_LOADER_FORCE_LE

@@ -1,3 +0,0 @@
-.\" $FreeBSD$
-Set to force the powerpc boot loader to launch the kernel in little
-endian mode.