parisc: Use zdep for shlw macro on PA1.1 and PA2.0

The zdep and depw,z mnemonics generate the same code. The assembler will
accept the depw,z mnemonic when generating PA 1.x code. The zdep
mnemonic is okay when generating PA 2.0 code. This patch changes depw,z
to zdep in the current shlw macro, while the binary code will be the
same.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: John David Anglin <dave.anglin@bell.net>