arm64/cpufeature: Refactor conditional logic in init_cpu_ftr_reg()

arm64/cpufeature: Refactor conditional logic in init_cpu_ftr_reg()

Unnecessarily checks ftr_ovr == tmp in an extra else if, which is not
needed because that condition would already be true by default if the
previous conditions are not satisfied.

		if (ftr_ovr != tmp) {
		} else if (ftr_new != tmp) {
		} else if (ftr_ovr == tmp) {

Logic: The first and last conditions are inverses of each other, so
the last condition must be true if the first two conditions are false.

Additionally, all branches set the variable str, making the subsequent
"if (str)" check redundant

Reviewed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Hardevsinh Palaniya <hardevsinh.palaniya@siliconsignals.io>
Link: https://lore.kernel.org/r/20241115053740.20523-1-hardevsinh.palaniya@siliconsignals.io
Signed-off-by: Will Deacon <will@kernel.org>