ARM: dts: msm: use same label for rpm and gcc

clock_rpm isn't used on msmtellurium any more. Both clocks
are managed using same phandle clock_gcc.

Change-Id: I5269b2a78bee0adb5fe6c64714bb9e48dc016ef9
Signed-off-by: Arun KS <arunks@codeaurora.org>