arm64/sme: Fix tests for 0b1111 value ID registers

For both ID_AA64SMFR0_EL1.I16I64 and ID_AA64SMFR0_EL1.I8I32 we check for
the presence of the feature by looking for a specific ID value of 0x4 but
should instead be checking for the value 0xf defined by the architecture.

This had no practical effect since we are looking for values >= our define
and the only valid values in the architecture are 0b0000 and 0b1111 so we
would detect things appropriately with the architecture as it stands even
with the incorrect defines.

Signed-off-by: Mark Brown <broonie@kernel.org>
Fixes: b4adc83b

 ("arm64/sme: System register and exception syndrome definitions")
Link: https://lore.kernel.org/r/20220607165128.2833157-1-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>