layerscape: Add CONFIG_NVMEM_LAYERSCAPE_SFP kernel configuration option

The kernel configuration option is now available on kernel 5.10 and
5.15, add it to the config for 5.15 too.

Fixes: 8dfe69cdfc5c ("kernel: update nvmem subsystem to the latest upstream")
Signed-off-by: Hauke Mehrtens <[email protected]>

target/linux/layerscape/armv8_64b/config-5.15

@@ -544,6 +544,7 @@ CONFIG_NUMA=y
 CONFIG_NUMA_BALANCING=y
 CONFIG_NUMA_BALANCING_DEFAULT_ENABLED=y
 CONFIG_NVMEM=y
+# CONFIG_NVMEM_LAYERSCAPE_SFP is not set
 # CONFIG_NVMEM_SPMI_SDAM is not set
 CONFIG_NVMEM_SYSFS=y
 CONFIG_OF=y