parisc: Fix build of compressed kernel even with debug enabled

With debug info enabled (CONFIG_DEBUG_INFO=y) the resulting vmlinux may get
that huge that we need to increase the start addresss for the decompression
text section otherwise one will face a linker error.

Reported-by: Sven Schnelle <svens@stackframe.org>
Tested-by: Sven Schnelle <svens@stackframe.org>
Cc: stable@vger.kernel.org # v4.14+
Signed-off-by: Helge Deller <deller@gmx.de>