perf: imx_perf: add support for i.MX91 platform

This will add compatible and identifier for i.MX91 platform.

Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20240924061251.3387850-2-xu.yang_2@nxp.com


Signed-off-by: Will Deacon <will@kernel.org>