[klibc] fix build failure on 64-bit parisc

[H. Peter Anvin]

Kyle McMartin wrote:
> On PA-RISC machines running in 64-bit mode, uname -m returns `parisc64'
> instead of `parisc.' Thus, we must sed this to match like a few
> other platforms.

Should we be building 64-bit parisc binaries in this case?
	
	-hpa