xtensa: fix atomic_decrement_if_positive() return value
xtensa: fix atomic_decrement_if_positive() return value

atomic_decrement_if_positive() returns the old value of &mem, not the
(sometimes undefined) value of __tmp.

Fixes the uClibc nptl/tst-sem3 test.

Signed-off-by: Baruch Siach <53ccad33e0625915318fb3bc832e5c1c413d1294@tkos.co.il>
Signed-off-by: Chris Zankel <711c73f64afdce07b7e38039a96d2224209e9a6c@zankel.net>

hjl-tools/uClibc,ffainelli/uClibc,ffainelli/uClibc,kraj/uClibc,kraj/uclibc-ng,kraj/uClibc,mephi42/uClibc,hjl-tools/uClibc,kraj/uClibc,majek/uclibc-vx32,kraj/uclibc-ng,groundwater/uClibc,majek/uclibc-vx32,hjl-tools/uClibc,groundwater/uClibc,hjl-tools/uClibc,foss-for-synopsys-dwc-arc-processors/uClibc,mephi42/uClibc,kraj/uClibc,foss-for-synopsys-dwc-arc-processors/uClibc,groundwater/uClibc,foss-for-synopsys-dwc-arc-processors/uClibc,wbx-github/uclibc-ng,brgl/uclibc-ng,ffainelli/uClibc,ffainelli/uClibc,kraj/uclibc-ng,majek/uclibc-vx32,wbx-github/uclibc-ng,brgl/uclibc-ng,brgl/uclibc-ng,ffainelli/uClibc,brgl/uclibc-ng,wbx-github/uclibc-ng,kraj/uclibc-ng,mephi42/uClibc,hjl-tools/uClibc,mephi42/uClibc,foss-for-synopsys-dwc-arc-processors/uClibc,groundwater/uClibc,majek/uclibc-vx32,groundwater/uClibc,wbx-github/uclibc-ng