[POWERPC] Fix powerpc vmlinux.lds.S

Sam's recent change in 7664709b
broke things for us because we ended up with *(.text.*) before
*(.text), whereas previously *(.text) was first.  This was
important because the start of the text section contains the
kernel entry point.

In fact, we don't need that *(.text.*) thing anymore and it
incorrectly matched .text.init.refok, thus putting it before
.text. .. ouch !

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>