Fix typos

Signed-off-by: Tom Cosgrove <tom.cosgrove@arm.com>
diff --git a/library/bignum_core.h b/library/bignum_core.h
index b079850..d9e16ee 100644
--- a/library/bignum_core.h
+++ b/library/bignum_core.h
@@ -623,7 +623,7 @@
  * \param[in]     A         The MPI to convert into Montgomery form.
  *                          Must have the same number of limbs as the modulus.
  * \param[in]     N         The address of the modulus, which gives the size of
- *                          the base `R` = 2^(biL*m->limbs).
+ *                          the base `R` = 2^(biL*N->limbs).
  * \param[in]     AN_limbs  The number of limbs in \p X, \p A, \p N and \p rr.
  * \param         mm        The Montgomery constant for \p N: -N^-1 mod 2^biL.
  *                          This can be determined by calling
@@ -661,7 +661,7 @@
  * \param[in]     A         The MPI to convert from Montgomery form.
  *                          Must have the same number of limbs as the modulus.
  * \param[in]     N         The address of the modulus, which gives the size of
- *                          the base `R` = 2^(biL*m->limbs).
+ *                          the base `R` = 2^(biL*N->limbs).
  * \param[in]     AN_limbs  The number of limbs in \p X, \p A and \p N.
  * \param         mm        The Montgomery constant for \p N: -N^-1 mod 2^biL.
  *                          This can be determined by calling