MIPS: bootm: drop obsolete Qemu specific bootm implementation

MIPS: bootm: drop obsolete Qemu specific bootm implementation

The Qemu specific bootm implementation was intended for a special
Qemu target in Linux kernel. But this target has been dropped in
v2.6.25-rc1 by commit 302922e5f6901eb6f29c58539631f71b3d9746b8

    Author: Ralf Baechle <ralf@linux-mips.org>
    Date:   Tue Jan 29 10:15:02 2008 +0000

    [MIPS] Qemu: Remove platform.

    The Qemu platform was originally implemented to have an easily supportable
    platform until Qemu reaches a state where it emulates a real world system.
    Since the latest release Qemu is capable of emulating the MIPSsim and
    Malta platforms, so this goal has been reached.  The Qemu plaform is also
    rather underfeatured so less useful than a Malta emulation.

Thus the special bootm implementation is obsolete by now and can be
dropped. The Qemu support in U-Boot is going to be replaced by MIPS Malta
board support.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>