libm: krait: Fix build warning for e_pow.o

e_pow.o given more than once in the same rule. Remove extra arm/e_pow.S
reference in libm/Android.mk.

(cherry picked from commit a730ffa1195ad85a0e77afc9bf2cb78754b5985c)

Change-Id: I5a4c38e838978e0538697c8a5df1e97f1175e39e
(cherry picked from commit 1002139bee177b90dc011b8ac9f24c4696cf82b6)
(cherry picked from commit 99146f7c6c1ee984608ad705b67f562fb9006cd0)
1 file changed