nfc: Remove checks for nla_data returning NULL

nfc: Remove checks for nla_data returning NULL

The implementation of nla_data is as follows:

static inline void *nla_data(const struct nlattr *nla)
{
	return (char *) nla + NLA_HDRLEN;
}

Excluding the case where nla is exactly -NLA_HDRLEN, it will not return
NULL. And it seems misleading to assume that it can, other than in this
corner case. So drop checks for this condition.

Flagged by Smatch.

Compile tested only.

Signed-off-by: Simon Horman <horms@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20250617-nfc-null-data-v1-1-c7525ead2e95@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>