arm64: zynqmp: Fix compiler warnings in mp.c

arm64: zynqmp: Fix compiler warnings in mp.c

make W=1 generates the following warning in cpu_disable, cpu_status and
cpu_release functions.

arch/arm/mach-zynqmp/mp.c:166:16: warning: comparison of unsigned expression
in '>= 0' is always true [-Wtype-limits]
166 |         if (nr >= ZYNQMP_CORE_APU0 && nr <= ZYNQMP_CORE_APU3) {
    |                ^~

Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@amd.com>
Link: https://lore.kernel.org/r/20221004053454.25470-1-venkatesh.abbarapu@amd.com
Signed-off-by: Michal Simek <michal.simek@amd.com>