mtd: rawnand: qcom: parse read errors for read oob also

read_page and read_oob both calls the read_page_ecc function.
The QCOM NAND controller protect the OOB available bytes with
ECC so read errors should be checked for read_oob also.
This patch moves the error checking code inside read_page_ecc
so caller does not have to check explicitly for read errors.

Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>