rpm: enable system_pmdk bcond for SUSE builds

rpm: enable system_pmdk bcond for SUSE builds

ecb8d2cae2c063acf4e7e1bffed887d52117762f disabled the system_pmdk bcond for all
build targets based on the fact that pmdk 1.10 was not available on any of them.

Now that openSUSE Tumbleweed ships pmdk 1.11, we re-enable the system_pmdk bcond
to fix the master build for openSUSE Tumbleweed.

Since openSUSE Tumbleweed is the *only* SUSE build target master supports, there
is no need for greater granularity in the distro conditional here.

Signed-off-by: Nathan Cutler <ncutler@suse.com>