Currently the spi_mem_op to read from the flash is used in two places:
spi_nor_create_read_dirmap() and spi_nor_spimem_read_data(). In a later
commit this number will increase to three. Instead of repeating the same
code thrice, add a function that returns a template of the read op. The
callers can then fill in the details like address, data length, data
buffer location.
Signed-off-by: Pratyush Yadav <p.yadav@xxxxxx>