arm_mpam: Fix monitor instance selection when checking for hardware NRDY

arm_mpam: Fix monitor instance selection when checking for hardware NRDY

In _mpam_ris_hw_probe_hw_nrdy() a new register value to select the first
monitor and relevant RIS is prepared in mon_sel. However, it is written to
the monitor value register, e.g. MSMON_CSU, rather than MSMON_CFG_MON_SEL.

As MSMON_CFG_MON_SEL is a 32 bit register update the type of mon_sel to
u32.  Write mon_sel to the intended register, MSMON_CFG_MON_SEL.

Fixes: 8c90dc68a5de ("arm_mpam: Probe the hardware features resctrl supports")
Cc: <stable@vger.kernel.org>
Signed-off-by: Ben Horgan <ben.horgan@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>